Bill Spencer, Jr. is the previously unknown son of publishing magnate Bill Spencer, Sr. They had never been close, but when the elder Spencer died, Bill came to Los Angeles to carry out his father's last wish: to avenge his one true love, Stephanie Forrester, by destroying Eric Forrester and Forrester Creations. Bill encouraged Stephanie, who had defected to rival fashion house Jackie M, to rant about the Logans in a damaging video blog. Eric refused to sell Forrester to Bill, who blackmailed Eric with the knowledge that Eric had hired an illegal immigrant years before. But Stephanie recorded the conversation and threatened to go public unless Bill backed off.

A consummate womanizer, Bill put the moves on an unresponsive Donna Logan. Later, Bill met Donna's sister, Katie Logan. Fresh from a breakup with Nick Marone, Katie got drunk at the Cafe Russe, but Bill chose not to take advantage of her. Instead, Bill got to know Katie, who challenged Bill's tendency to be a shark. When Katie learned of Bill Sr.'s directive, she questioned Bill's feelings, but Bill insisted his devotion was genuine and proposed. Bill knew Katie wanted to do something special after a second chance at life via a heart transplant, so when Bill finally secured Forrester Creations, he made Katie its CEO.

Young Steffy Forrester was intrigued by Bill and kissed him. But Bill still married Katie in her old San Fernando Valley neighborhood. Bill laughed when the Forresters unsuccessfully tried to sabotage him by creating the ugly Dare fashion line. Bill nearly gave in to his attraction to Steffy until Steffy stole Katie's engagement ring and swore she'd take it to Katie if Bill didn't return Forrester to her family. Bill fumed and vowed revenge, but secretly admired Steffy's ruthless behavior.

Bill befriended Donna, whose marriage to Eric was in trouble, and encouraged her to ask for half of Eric's Forrester stock in a divorce. Now thinking of the Logans as family, Bill offered to join forces with patriarch Stephen Logan in a fight against Eric. Bill blasted his right-hand man Justin Barber for exposing Donna's sister, Brooke Logan, in a sex scandal, yet himself exposed Brooke's daughter, Bridget Forrester, in a paternity scandal, saying he'd already given the Logans a free pass. Bill bought the 12.5% of Forrester that Donna had been awarded and later tried to buy Steffy's 25% share.

Bill soon learned that Spencer Publications intern Liam Cooper was his son, the result of a long-ago affair with Kelly Cooper, who had died. Barracuda Bill clashed with the forthright Liam, disapproving of Liam dating the gentle Hope Logan; Bill put pressure on Hope's ex-boyfriend Oliver Jones to take Hope back and threw a party declaring Liam "the world's most eligible bachelor." But Bill went ballistic when social climbing Amber Moore named Liam as the father of her baby. When a $500,000 bribe didn't work, Bill moved Amber into a cliff house with a faulty balcony, hoping Amber would fall to her death. When Katie learned of Bill's plot, she walked out, only agreeing to return if Bill sought therapy.

Bill snarked his way through sessions with Dr. Taylor Hayes and seemingly made up with Katie off-screen. Then Steffy's brother, Thomas Forrester, went missing at sea, so Bill used his massive resources to rescue Thomas; Bill fell for Steffy and began a full-blown affair, but before they could consummate it, Taylor caught them in bed. Taylor exposed Bill at Katie's surprise vow renewal ceremony, causing Katie to have a heart attack. Though Bill had been ready to leave Katie for Steffy, he opted to stay with Katie.

After Steffy fell for Liam, Bill sent Steffy to seduce Liam away from Hope. When Hope saw Liam kissing Steffy, she left her engagement ring on Liam's mantel; Bill capitalized on Liam offering the ring to Steffy by sending them to Aspen to get married. Hope followed, so Bill had her trapped in a gondola where she was forced to watch the ceremony. Knowing Liam wanted to return to Hope, Bill took advantage when Steffy was injured in an ATV accident and faked an MRI to read that Steffy had a life-threatening blood clot so Liam would feel obligated to stay with Steffy. Katie found out and threatened to tell Liam, so Bill locked Katie in a tower, finding himself alone after Katie escaped and exposed him. Before long, Bill and Katie again resolved their problems off-screen, though Bill fantasized about Brooke one night at dinner.

Bill's half-sister, Karen Spencer, relocated from New York with Danielle. When Bill found out Danielle was Karen's spouse, Karen confessed she'd been secretive about her because she feared Bill's reaction, but Bill accepted the couple. Bill wouldn't accept Hope, however, and persecuted her by siccing paparazzi on her and bribing a warden to break Hope's father, Deacon Sharpe, out of jail, hoping Deacon would prevent Hope from marrying Liam in Italy. Later, Katie told Bill she was pregnant; Bill ordered her to abort, admitting he was afraid heart patient Katie might die carrying a baby. Bill warmed to the idea of becoming a father, but when Katie found Deacon in Bill's office and learned of Bill's illegal activities, Katie went into premature labor and flatlined on the operating table. Katie recovered, but Bill only escaped prosecution because the Logans wanted to protect baby Will. Deacon tried to blackmail Bill, who threatened to have Deacon killed.

Katie slid into postpartum depression and disappeared; Bill and Brooke followed clues to Aspen, finding a note from Katie asking for a divorce. Bill and Brooke kissed, but when they returned home, Katie, who had been terrified of orphaning Will and saw Brooke as a motherly replacement, announced she wanted her life back. Bill continued to think of Brooke and encouraged her to reboot her once-successful lingerie line, which annoyed Katie. Meanwhile, Karen's daughter, Caroline Spencer, got wind of Bill's association with Deacon and fell over a balcony while confronting Bill; Bill briefly stood accused of pushing Caroline. Hope eventually found out about Deacon and bashed her way into Bill's house with a golf club, but when Liam shunned Bill, Dollar Bill lived up to his name by stabbing himself with his sword necklace to get Liam's sympathy, secretly placing his money pouch under his shirt to cushion the blow.

Bill began drinking excessively and balked at the intervention Katie arranged, so Bill asked Brooke to keep it a secret when he crashed his car driving drunk. When Katie found Bill convalescing in Brooke's bed, Katie took off her wedding ring and demanded a divorce; Bill now felt free to make love to Brooke, but their afterglow was interrupted by the news that Katie had been hospitalized with heart failure. Katie wanted Bill back so Bill tried to make it work, though Bill was thrown when Brooke reported miscarrying his baby. Taylor found out about Bill's affair with Brooke and exposed them during Brooke's birthday party; Bill agreed to give Katie 1% of Spencer Publications in their divorce, but found himself out of a job when Katie sold her share to majority stockholder Karen, who fired Bill and made Katie CEO.

When Caroline lamented that her beau, Rick Forrester, had eyes for Maya Avant, Bill learned that Maya had been wrongly convicted of a crime and was not to go near her ex-boyfriend, Jesse Graves. Bill arranged for Maya to run into Jesse and be photographed with him; Maya resisted Bill's blackmail, and Rick locked Bill in a mock jail cell to teach him a lesson. Later, Bill discovered he had another long-lost son in Wyatt Fuller as a result of a short fling with jewelry designer Quinn Fuller. Wyatt and Bill clashed over Bill's current affair with Brooke until Brooke played peacemaker for them.

It made Bill happy being able to babysit Will, but Bill didn't know that Katie was only allowing it so she could spy on Bill and Brooke with hidden cameras. When Bill found out, he followed Brooke to Monte Carlo and convinced her to give their relationship a chance. While mountain climbing in Aspen, Bill nearly fell to his death, then suddenly reconciled with Katie, asking her to sign documents that would return control of Spencer Publications to him and give him join custody of Will. Bill ran to Brooke bragging how he'd tricked Katie, but Brooke replaced his papers with leaves and threw him out.

Bill sparred with Quinn, who felt Bill favored Liam over Wyatt; Quinn jabbed Bill with his sword necklace and licked it from her finger. Later, unhappy that Brooke had agreed to remarry longtime paramour Ridge Forrester, Bill got drunk and had raucous S&M sex with Quinn. After Katie stopped the wedding because she had fallen for Ridge herself, Bill and Brooke slowly found their way back together again. Bill was pleased when Brooke produced the papers Katie had signed and used them to reinstate Bill as CEO of Spencer.

Bill planned an elaborate wedding for Brooke in the United Arab Emirates, shocked when Ridge, who bristled at the idea of becoming a stepfather to R.J. Forrester, Ridge's son with Brooke, interrupted the ceremony with a selfie Quinn had taken while in bed with Bill. After Ridge punched Bill and dragged Brooke away to a helicopter, Bill ordered Justin, the pilot, to "cool him off" -- Justin banked the chopper, and Ridge fell into the Persian Gulf. Having not intended to hurt Ridge, Bill organized a search team and was relieved when Ridge returned with an impaired memory. Bill pressured Brooke to marry him immediately, but soon Ridge traced the accident back to Bill and commandeered Bill's helicopter, threatening to throw Bill out of it unless he confessed. Bill lost Brooke when she was told how Bill had rendered Ridge unable to design.

After Ridge's ability was restored, Bill interrupted Deacon's proposal to Brooke with a proposal of his own; Bill hid his hurt when Brooke moved to Milan to find herself. Bill reconnected with Katie, outraged to hear that ladykiller Ridge had betrayed Katie by kissing Caroline. Bill had a knock-down-drag-out fight with Ridge, accidentally referring to Caroline as his daughter instead of his niece. Continuing to find himself in the role of referee between sons Liam and Wyatt, who were fighting over Hope, Bill tried to goad Quinn into jumping off a building for her inadvertent part in Hope miscarrying Wyatt's baby.

Bill wanted to reunite with Katie, who was gunshy after his affair with Brooke. After Bill made Katie vice president of Spencer and deemed himself a changed man, he convinced Katie to accept his proposal. During Bill and Katie's wedding, Brooke, who had come home, uncharacteristically made drunken asides; Bill assured the worried Katie that Brooke wasn't an alcoholic.

Later, Bill was enraged when Rick, who had married Caroline and become CEO of Forrester, retaliated against Caroline for her involvement with Ridge by shooting at them and taking Maya as his mistress. Bill threatened to make Maya's prison past stick, but found the perfect ammunition when Liam and Wyatt discovered that Maya was actually transgender, which Rick knew nothing about. Ignoring opposition from Katie and his sons, Bill exposed Maya in his magazines. Bill toyed with Rick and Ridge when they came to him separately asking Bill to transfer his 12.5% stake in Forrester and give them controlling interest in the company; when Bill told Rick that Maya would have to go because she was a disgrace, Bill found Rick's fist in his face. Ultimately, Bill signed his 12.5% to Liam, who combined shares with Ridge, Steffy, and Thomas and forced Rick out of the CEO chair.

At Katie's urging, Bill apologized to Maya for making a public spectacle of her, adding that he respected Maya for withstanding it. Bill continued counseling his embattled sons, refusing Wyatt's request to bankroll a new fashion house for his girlfriend, Ivy Forrester. Bill was pleased when Liam and Steffy reunited; Bill even played football with the Forrester men at Thanksgiving.

After Katie insisted they offer Brooke a job editing Eye on Fashion, Bill was speechless as Brooke admitted she still thought of him romantically. Finding out Katie had overheard, Bill continually tried to convince her nothing was happening with Brooke and became very concerned about Katie's increased alcohol consumption after little Will couldn't rouse her. Elsewhere, Bill was dismayed when Liam blew town and hired Wyatt to replace him; Bill grudgingly accepted Wyatt's deepening relationship with Steffy and served as best man at their wedding. But Bill was floored when a memory impaired Liam returned from weeks of being held by Quinn and believing he was Quinn's husband. Bill grilled Quinn's ex-husband, Deacon, regarding Quinn's whereabouts and insisted that Liam press charges.

When Katie told Bill that Ridge's son, Thomas, had fathered Caroline's son, whom Ridge was passing off as his own, Bill ran to Brooke and wanted to publish the story in his magazines; Bill faced Katie's wrath about betraying her confidence and saw no reason not to resume his affair with Brooke once Katie walked out. Bill wanted to remain married to Katie but fool around with Brooke, setting up a private love nest in his office. Bill threatened to cut Liam off for not respecting Wyatt's marriage to Steffy until Liam found the secret room and flamed Bill for his hypocrisy.

Bill worked on a resistant Brooke as he began divorce proceedings with Katie, who asked for Bill's 12.5% stake in Forrester to help Ridge stop Quinn, since Quinn had become involved with Eric. Bill wouldn't give Katie the stock but offered it to Brooke as incentive for marrying him. Bill expedited his divorce papers by claiming residency in Nevada and thrilled when Brooke accepted his proposal, but Bill's wedding plans hit a snag when Brooke's son R.J. returned and vehemently objected to Bill marrying his mother. An impatient Bill reluctantly agreed to delay the wedding when Brooke asked for time to get R.J. used to the idea.

Bill finally got Brooke to the altar but fumed when he found Ridge trying to sway Brooke's affections just before the ceremony. Feeling the day was tainted, Bill walked out on Brooke, swearing she would still be Mrs. Spencer one day. Bill agreed to a day of bonding with R.J., teaching the boy to box and showing him a secret bunker filled with guns and money. Bill soon announced to Brooke they were eloping and that she should tell Ridge to back off, but Bill got the surprise of his life when Brooke came back from confronting Ridge only to reveal she was returning to him. A persistent Bill repeatedly insinuated himself into Brooke's life and tried to drive home his point that Ridge was only going to hurt her again.

Bill wanted to build a high-rise on the spot of the old Spectra Fashions building, which had fallen into rack and ruin. Annoyed when its owner, C.J. Garrison, decided to give his cousin, Sally Spectra, a chance to revive the business instead, Bill published a scathing review of Sally's first fashion collection in an attempt to drive her out. Later, Bill attended Liam's wedding to Steffy in Australia, but spent most of his time Down Under moping over Brooke's upcoming marriage to Ridge until Bill went for a walk and found Brooke alone on her wedding day.

Bill happily accepted Brooke's proposal and readied to swoop in on Spectra Fashions so he could build his skyscraper until Sally's boyfriend, Thomas, invested $100,000 in Spectra and saved the company. Bill licked his wounds by arranging a wedding for Brooke, overjoyed to finally exchange vows with her and honeymoon in Paris. Bill was unsurprised to learn that Deacon had tried to kill Quinn and refused Deacon's request for bail money off-screen.

Realizing tearing Thomas and Sally apart would allow him to also tear down Spectra and finally put up his building, Bill lied to Thomas that Caroline was dying so he would run back into her arms for the sake of their son, Douglas Forrester. With Thomas out of his way, Bill set his sights on Spectra and ordered Liam to write a new battery acid review about Spectra's latest fashion preview. When Liam confronted him about making up Caroline's illness, Bill threatened to disown him if he didn't get on board. After a small electrical fire broke out during Spectra's preview because of a faulty socket, Bill took Justin's suggestion to capitalize on it and arranged to burn Spectra down. Bill smugly admitted his deed to Liam but didn't realize his confession was being recorded; when Liam threatened to go to the police if Bill didn't step down as CEO of Spencer Publications, Bill punched Liam in the face.

Faced with Brooke's continued questions about his "leave of absence," Bill revealed he'd arranged the Spectra fire, causing Brooke to walk out on him; Bill blamed Liam and vowed revenge. Bill found himself more appreciative of Steffy, who seemed to be the only family member to offer any real support. After hiring a hacker to delete Liam's recording of his confession, Bill took his CEO seat back and installed Liam and Wyatt as his equal right-hand men, secretly doing so in order for him and Wyatt to be able to vote against Liam and demolish Spectra. Believing Liam and Sally had abandoned their protest sit-in, Bill pushed the button, only to discover in horror that Liam had gone back into the building first; Bill and Steffy risked their lives to save Liam and Sally from the rubble.

Learning Liam had kissed Sally while trapped, Bill told a devastated Steffy that Liam wasn't good enough for her and wound up making love to her. After Steffy declared she was staying with Liam and swore Bill to secrecy about their tryst, Bill sulked to the point of distraction. When Steffy revealed she was pregnant, Bill realized the child could be his and talked Steffy into having a paternity test to be sure; the results revealed the baby was Liam's. Despite catching hell from Liam and most of the family for bedding Steffy, Bill stepped up his pursuit of her and proposed even though Steffy continually rejected him.

Bill enraged Sally when he reneged on his promise to rebuild Spectra, and had a fit himself when Wyatt and Katie announced their engagement; Bill disowned Wyatt and promised to take Will away from Katie. Home alone one windy night, Bill was shot in the back and had Ridge arrested for the crime. However, Bill recanted after Liam confessed pulling the trigger while suffering the effects of a concussion. When the returning Taylor revealed herself as the shooter and pulled a gun on Bill again, Bill agreed to keep Taylor out of jail as a favor to a begging Steffy. Bill used Taylor's culpability to coerce Steffy into signing Liam's annulment papers, then faked romantic scenes to make Wyatt think he was still carrying on with Steffy, knowing Wyatt would run straight to Liam with the news. Bill attempted to bribe Wyatt into keeping quiet about his scheme, but threw Wyatt out of his life again when Wyatt told Liam the truth, which put the kibosh on Liam's wedding to Hope.

After his threats to have Taylor jailed if Steffy married Liam instead of him didn't work, Bill had Justin snap a photo of Liam embracing a pregnant Hope. Bill was overjoyed when Steffy finally agreed to marry him and happily agreed to give her his 12.5% stock in Forrester Creations as a wedding gift; Bill still presented Steffy with the shares even after she called the wedding off. Bill took heat from Katie for being so busy chasing Steffy that he neglected Will, so Bill tried to spend more time with his youngest son, only to find the boy didn't want to. Bill clashed with Ridge's brother, Thorne Forrester, whom Katie was seeing; Bill vowed to crush them both when Katie filed for sole custody of Will and married Thorne ahead of the hearing.

Bill's feelings for Brooke resurfaced when she was nearly the only one who had his back in the custody battle, which Bill ended up losing. Bill kissed Brooke and found himself confronted by Ridge and Thorne; the men fought, and Bill took a tumble from his second-floor balcony. Determined to change, Bill didn't press charges against the Forrester brothers and made an effort to be more involved in Will's life. Soon, Bill learned from Justin that Ridge had influenced the judge in Will's custody case, so Bill secretly recorded Ridge and the judge and had their phones hacked, then summoned them to his office and put them on blast, only to let them go in exchange for Katie giving Bill joint custody of Will again.

Bill put off the police when they returned for more information about his shooting; Bill assured a worried Taylor that he would keep his promise about not turning her in, but when Taylor got increasingly frantic about Bill sleeping with Steffy and ruining her marriage, Bill threw Taylor out. Bill was concerned when Liam relayed that Brooke and Hope now also knew about Taylor's crime. Later, Bill moved heaven and earth to have Liam flown through a windstorm to Catalina Island, where Hope had gone into labor. Hearing from Brooke that Hope was having a rough delivery, Bill pulled more strings so he, Brooke, and Ridge could also fly to Catalina; when they arrived there, Bill joined Ridge and Brooke in mourning the loss of Hope's baby, who would have been their grandchild.

At Will's behest, Bill began spending more time with him and Katie as a family. Bill asked Wyatt to return to Spencer Publications and agreed to Wyatt's stipulation that Bill revive Spectra Fashions to make up for destroying Sally's career; Bill promised Sally he'd be the new fashion house's owner in name only, but insisted that it be called Spencer Fashions. Bill wasn't disappointed when Sally got a better offer from Forrester Creations and decided to stay there. Meanwhile, Bill kept finding himself set up on expensive dates with Katie, who had split from Thorne; when Bill learned Will was paying for the dinners with his credit card, Bill was more amused than annoyed. The resulting closeness with Katie inspired Bill to propose to her; Bill was bruised when Katie turned him down, unsure if she could trust him romantically again.

Bill dodged another paternity bullet when it seemed a long-ago one-nighter in Las Vegas with casino boutique employee Shauna Fulton had produced a daughter, Florence Fulton; as Wyatt and Flo were high school sweethearts, Bill panicked that Wyatt and Flo might actually be brother and sister. However, it turned out Flo was the daughter of Brooke's deceased brother, Storm Logan. Bill continually tried to convince Katie his renewed feelings for her were legitimate and only fully realized he was in love with her when Shauna came on to him; Bill shared a laugh with Katie when he learned Katie had put Shauna up to it. Bill reunited with Katie and happily shared the news with an ecstatic Will.

Bill was furious when he learned Hope and Liam had been the victims of obstetrician Reese Buckingham, who stole Hope's baby, switched it with a dead one, and used money from its adoption to pay gambling debts; Bill roared that Reese should pray Ridge's people found him before Bill's did, then welcomed Beth into the family and bonded with Liam over the ordeal. Later, Bill was at Katie's side when she was hospitalized with kidney failure relating to having taken anti-rejection medication as a heart recipient for years; Bill felt helpless when none of Katie's relatives were a donor match. Bill's joy at a donor being found was tempered when it turned out Katie's life had been saved by Flo, who had been an accomplice in his granddaughter Beth's illegal adoption.

When Katie returned from a doctor follow-up seeming secretive, Bill learned that Katie had run into Sally at the hospital and found out Sally was dying of a terminal illness. Bill tried to compliment Sally and couldn't help feeling impressed by Flo's decision to let Wyatt "reunite" with Sally in her final days. Meanwhile, Bill sided with Brooke, who had hit a wall with Ridge over whether or not Thomas was unstable and obsessed with Hope; Bill comforted Brooke, but it led to an unexpected kiss. After Brooke was proven right about Thomas, Bill attended Ridge and Brooke's reunion party, which was interrupted by a video of Bill and Brooke kissing that Quinn had uploaded to a digital picture frame. Bill took a punch in the face from Ridge and watched Katie walk out on him. Bill repeatedly tried to convince Katie to come back to him, but met with cordial yet firm rejections.

Out driving, Bill accidentally hit a motorcyclist with his car and was horrified to learn it was Steffy. Bill was truly remorseful and held vigil at the hospital, blaming himself for Steffy's injuries when most of the family assured him it had only been an accident. Bill continued feeling responsible after Steffy became addicted to painkillers while recovering.

Bill continued in his attempts to wear Katie down and get her to come back to him, enlisting Brooke and Donna to aid him. Meanwhile, Bill took a side trip to Genoa City, Wisconsin, where it was discovered Bill knew bigwig Victor Newman and once dallied with department store heiress Lauren Fenmore. Bill ran into Sally, who had moved to the Midwest after lying about her terminal illness as part of a scheme to win Wyatt back; Bill warned Sally to stay away from his family.

Bill let Liam drive his fanciest car and shared Liam's shock when Liam accidentally hit Vinny Walker, who had fixed Steffy's paternity to read that Liam was the father of her child instead of Steffy's boyfriend, John "Finn" Finnegan. After Liam passed out on the scene, Bill got rid of Vinny's phone and wallet, fearing Liam's connection to Vinny would make the police think Liam ran Vinny down on purpose. Bill then sold his car to a sheik in the Middle East and demanded that the haunted Liam keep quiet about what happened and act like everything was normal. Bill had a hard time containing himself when the cops indeed arrived to question Liam about Vinny's death. Bill repeatedly harassed Liam into keeping quiet, but after Liam finally confessed and was arrested, Bill admitted his part in the cover-up and also went to jail, hoping to take the heat off of Liam.

Bill couldn't understand it when his usually reliable right-hand man Justin seemed to be dragging his heels while working on Bill and Liam's defense. Bill and Liam were freed once it came out that Vinny had thrown himself in front of their car on purpose to frame Liam, but Bill's feelings of betrayal ran deep when he learned that Justin had taken advantage of his incarceration to position himself as the head honcho of Spencer Publications. An emotional Bill turned his back on his former best friend.

Bill continued to give Katie the space she had asked for, but eventually approached her again for a reconciliation, getting rejected when Katie wanted a man who would love only her. Later, when Deacon was released from jail for shooting at Quinn and wanted a relationship with Hope, Bill warned Liam to protect his family. For the show's 35th anniversary, Bill was one of several of Brooke's loves who appeared in a dream to remind her of her value as she went through a rough time with Ridge.

After dining with Wyatt at a new seafood restaurant on the wharf, Bill left by its back alley and found a mute homeless woman there. Having discovered a level of compassion, Bill took the woman home and brought in a doctor when she refused to go to the hospital. Bill was floored when Liam arrived and identified the woman as Li Finnegan, whose adoptive son, Finn, had been killed by his biological mother, career criminal Sheila Carter. When Bill learned from Li that Finn was alive and being held by Sheila, Bill aided in Finn's rescue and took Finn to Monte Carlo, where Finn reunited with Steffy. Bill was impressed that Li had gone up against Sheila and realized that he and Li had many things in common.

Bill decided to sell his property in Aspen and encouraged Steffy and Taylor to have a look. Despite having just waged another failed campaign for a reunion with Katie, the first thing Bill did was run to Brooke when he heard that Ridge had dumped Brooke for Taylor. After Katie's new beau, Carter Walton, called Bill out for his fickleness, Bill demanded that Carter stay away from "his" Katie. Soon after, Bill became romantically involved with a fugitive Sheila -- off-screen, Bill had bonded with Sheila, who had noticed the dejected Bill and followed him. To keep Sheila out of jail, Bill bought off a judge and threatened to turn Taylor in for shooting him years earlier if Steffy and Finn testified against Sheila. Bill received visits from horrified loved ones but championed his relationship with Sheila.

Bill held his ground against his objecting family, assuring Sheila she was the woman for him and letting her know that she could open up to him about her past. It was later revealed that Bill was working with the absent Ridge, as well as the FBI, in an attempt to lock Sheila up permanently. Disgusted by his "romance" with Sheila, Bill forced himself to propose to her, after which he extracted a confession from her about a long-ago murder she had committed. While gloating to Ridge on the phone, Bill was caught by Sheila and struggled with her, causing her to tumble over the same two-story balcony that he once had. After Sheila emerged from her fall unscathed, Bill followed her to Deacon, whom Bill and Ridge had recruited for their sting, and Bill watched as Sheila had a heart attack before her arrest.

It took a lot of explaining for Bill and Ridge to convince their families that Bill's involvement with Sheila had been a ruse. Bill received a slap, then a kiss, from Katie, after which Bill decided to pursue Katie once again, despite her growing relationship with Carter. However, Bill ran into a woman he thought he recognized and later found out she was Penelope "Poppy" Nozawa, with whom he'd had a fling some 20 years earlier at a music festival. Bill persisted when Poppy initially denied their connection and won a date with her, during which they reminisced about their time together. Bill learned that Poppy had a daughter, Luna Nozawa, and wondered if he could be Luna's father, since the timing lined up, but Bill had to take Poppy's word that he wasn't. Bill offered a sympathetic ear to Luna, who had been fighting with Poppy over Poppy's refusal to reveal the identity of her father; Bill confided that he had suspected Luna was his daughter, and that he still thought he might be.

Bill was thrown when Poppy reversed course and hinted that he was indeed Luna's father. Bill looked on as Poppy's sister, Li, a doctor, personally ran a DNA test; when Luna was confirmed to be Bill's daughter, a joyous Bill asked Poppy and Bill to move into his mansion with him. Bill also offered to adopt Luna and make her a Spencer. Bill listened to Katie's concerns about how fast things were moving with his new family and her worries that Will, who had been away at school, would have difficulties making the adjustment. Bill and Katie discussed their history and agreed that, while they'd always love each other, it was time to move on.

Bill told Poppy about Tom Starr, a formerly homeless rocker who had died after performing a comeback concert at Deacon's restaurant. Visiting the bistro, Bill ran into Justin, with whom he'd reconciled off-screen, and snarked that yet another staffer, Paul "Hollis" Hollister, had also died under Deacon's employ. Bill was stunned when Poppy admitted that she and Tom had been lovers during the same music festival where Bill and Poppy had had their own affair. Bill didn't know how to interpret Katie's claims that Poppy had killed Tom and Hollis, but when the police arrived to arrest Poppy, with telltale letters and poison from Poppy's apartment as evidence, Bill told the law to do what they had to and watched as Poppy was led away.

On the strong advice of Katie, Bill ran his own DNA test with Luna and learned that they were not actually father and daughter after all. It rattled Bill even more when Luna suddenly kissed him; Bill allowed her to stay on at his house despite her overture. Bill received vehement denials when he separately asked Poppy and Li if they had manipulated the original test.