Maria Santos arrived in Pine Valley in 1993 when she was recruited by Pine Valley Hospital to be their new neurosurgeon. Maria fell in love with Edmund Grey who was still carrying a torch for Brooke English. Eventually, Edmund and Maria fell in love, and they married. Shortly after, her college lover, Del Henry, came to Pine Valley. The truth emerged regarding Maria's college affair with Del, her college pregnancy and miscarriage, and Maria's resulting infection and infertility. Edmund and Maria's marriage became only stronger, and after several failed "in vitro" attempts, they opted for adoption. Maria and Edmund agreed to adopt the baby of Anita Santos' pregnant friend, and they named him Sam. However, they had to give him back when his birth mother changed her mind. Maria and Edmund separated over Sam's loss and after Edmund stopped Maria from fleeing the country with the baby and returned him to Kelsey, Maria had a one-night stand with her brother-in-law, Dimitri Marick, but later she reconciled with Edmund. In October 1996, Maria and Edmund were reunited with Sam after the baby's birth father convinced his birth mother to give Sam back to the Greys.

Maria and Edmund's child tragedies were not over. Shortly after her one-night fling with brother-in-law Dimitri, Maria found out that she was pregnant. In true soap opera fashion Skye Chandler seduced a lab technician and doctored Maria's results to make it look like Dimitri was the father (Edmund was). Skye hoped that Edmund would then fall for her. That never happened. When Erica learned about the baby's paternity, she confronted Maria in a cabin at Willow Lake during a horrible ice storm. Maria became overstressed and went into premature labor. Erica drove them to the hospital. But while en route, Erica's car skidded off the road, and everyone thought that the baby was lost in Willow Lake. Erica tried to track down the baby, and she found that a woman who lived near the lake had plucked the little girl from its icy waters. Erica convinced the woman that the baby was really hers and prepared to return the baby to Maria. Then she overheard Maria and Dimitri discuss the benefits of having lost the baby. Erica took matters into her own hands. Erica decided to keep the baby herself. For months Erica claimed that she had adopted the baby from Russia. Then Erica claimed the woman from the lake was the baby's mother and let Erica adopt her. The guilt built, and Erica decided to take the baby back to Edmund and Maria. The infant was reunited with Maria. The Greys charge Erica with kidnapping and two other felonies.

Later, during a flight back to Pine Valley after an awards ceremony out of state, Maria switched seats with Brooke to let her work with Edmond during the flight. Maria noticed an envelope in her briefcase; when she opened it, she found the letter revealing Maddie's true paternity. As Maria went to give Edmund the good news, the plane started shaking. It exploded and crashed. All but four people died - Brooke, Edmund, Maddie, and Jim Thomasen. Maria was stuck in her seat as the plane went down into the waters below.

In 2002, a woman by the name of Maureen Gorman came up as a match when little Lorenzo Santos, Mateo and Hayley's son, needed a liver transplant. Brooke and Tad traveled to Nevada to meet with the woman, whom Brooke believed was Maria, though Tad did not. Brooke came face to face with "Maureen," who turned out to be a dead-ringer for Maria. Later, though, when Tad met Maureen, she looked nothing like Maria (feeling uncomfortable, Maureen had asked a coworker to pose as "Maureen" for Tad). "Maureen" was afraid of Brooke and wondered why Brooke wanted to talk to her, so she called her friend, Dr. David Hayward, to ask for help. David knew "Maureen's" true identity, but urged her to stay away from Brooke and Pine Valley. "Maureen" traveled to Pine Valley anyway. There, she skulked around Wildwind, trying to find out who she was. She was mugged in the park and befriended by Aidan Devane, who saved her. Aidan helped keep her hidden, even after "Maureen" took Maddie away with her on Brooke and Edmund's wedding day. Brooke told Edmund the truth after their wedding ceremony, that she believed Maria was still alive. Edmund took off to find Maria. When the two came face to face, Maria told Edmund that she had no memory of him, their marriage -- or of anything else.

After trying for several weeks to live the life of Dr. Maria Santos Grey, and after many tense moments with Edmund about his expectations of her (Edmund tried to be patient, but he was so thrilled his wife was back he did not succeed very much), "Maureen" finally convinced everyone in Pine Valley to accept her as "Maureen Gorman." The only person who seemed satisfied with her as Maureen was Aidan, the one person who had never known Maria Santos Grey. The two of them began to fall in love. While Edmund found it difficult to watch his beloved wife and mother of his children with another man, he made it clear to everyone, including Maria's mother Isabella, that he understood Maria to be Maureen now, and he expected everyone else to do the same. In turn, "Maureen" let Aidan know that though she did not consider herself Edmund's wife, she was and would remain connected to him as Sam and Maddie's mother, which was fine with him. In spite of her growing anxiety about the return of her memories and the uncertainty of her future, "Maureen" accepted Aidan's proposal of marriage.

When Flanders murdered Chris Stamp in a local park and realized that little Maddie had witnessed the entire thing, she became the murderer's next target. Maria, Aidan, and Edmund joined forces to put the little girl into hiding to protect her. During these tense days, while in hiding with her daughter and Aidan, flickers of memories began to drift through Maria's mind, memories of Sam and Maddie and being their mother. When Maddie was tossed overboard, Maria/Maureen jumped in to save her. As she did, all of her memories returned. Maria was back. Maureen became a former, relatively small chapter in her life, and although she was grateful to Aidan and wanted to remain his friend, her heart belonged to Edmund. Maria told him she accepted his at times poor treatment of her over the past year and apologized for her own mistakes, then they made love for the first time in over half a decade. Maria moved back into Wildwind and fully reunited with her children and her mother.

When Carlos Reyes was admitted to the hospital following an attack by the Calatravas (the Argentinean gang who were trying to kill Carlos and his brother Pablo), Maria was his consulting doctor. She and Edmund became close friends with Carlos and Pablo. When Carlos died, Maria blamed herself for his death, fearing that the recent renewal of her medical license led to her making a mistake. She was prepared to resign. Soon the truth was revealed: A corrupt nurse employed by the Calatravas had killed Carlos. Edmund was shot and left paralyzed after helping Pablo deal with the Calatravas. Edmund wanted to undergo risky surgery that could restore the use of his legs, but possibly kill him. Fearful of losing her husband, Maria was adamantly against surgery. Edmund went through with the procedure and Maria did her best to support him. The surgery was not successful, and it appeared Edmund would be paralyzed for life.

Edmund's struggle to deal with his new condition caused strains for the Greys, as he became cold and distant. Complicating matters was the arrival of Zach Slater in Pine Valley. Maria found herself drawn to Zach, her attraction to him very much alive. Zach made it clear to Maria that he wanted to resume their relationship, but Maria vowed to be true to her husband. After Edmund overheard her talking with Zach, Maria came clean that they were involved while she was an amnesiac. Maria swore that her contact with Zach was going to end. As the distance between Edmund and Maria grew, Maria found herself drawn into Zach's world when she learned that he was really Alexander Cambias Junior, the presumed dead brother of Pine Valley rapist Michael Cambias. Zach had come to town to get the real story behind Michael's death, refusing to believe that the caring boy he once knew had become a monster. Sensing Zach's pain, Maria promised to help Zach come to terms with the truth about Michael, but kept this from Edmund. Zach asked Maria to keep his identity a secret, which Maria agreed to, yet another secret from Edmund.

Erica told Edmund that she had witnessed Maria and Zach in a close moment. Furious with Maria for her continued association with Zach, and with months of distance between them, Edmund initiated divorce proceedings. Maria told Edmund she loved him and would fight the divorce. The tension between them grew when Maria learned that Edmund had begun to get some feelings back in his legs, which he kept from her. Despite some real and unresolved feelings for Zach, Maria was determined to repair her marriage to Edmund. Edmund told Maria he loved her and that he stopped the divorce. Unbeknownst to Maria, Edmund had recovered from his paralysis and was determined to destroy Zach, and then divorce Maria. Soon after, Edmund was murdered. Ethan Ramsey, Zach's estranged son, told the police he witnessed Zach commit the crime. Zach told Maria that Edmund had been lying to her and could walk. Devastated over Edmund's death, Maria refused to believe Zach and blamed him for Edmund's murder. Zach was arrested and shocked Maria and Ethan when he confessed to the crime. Maria held firm to her belief that Edmund loved her and Zach was guilty. Brooke revealed to Maria that Edmund had planned on divorcing her shortly before he died. Maria refused to believe Brooke, and received another blow when Zach was released from prison, now claiming that he did not kill Edmund.

Zach was cleared of the murder, and Ethan revealed as a liar, when Jonathan Lavery was proven guilty. Maria felt terrible for believing the worst of Zach, and apologized to him, but Zach was furious and hurt. Reeling off this, Maria was shocked to learn that Edmund made Brooke the executor of his will and left Maria with nothing. A hurt Maria got drunk at a awards ceremony that was posthumously honoring Edmund, and lashed out at the town of Pine Valley. Zach cared for the drunken Maria, his feelings still evident. Sam and Maddie began to lash out at their mother for her behavior and her prior association with Zach. Maria apologized to Zach for all she had done, and told him that she never stopped loving him, but that she couldn't see him anymore. Her focus needed to be on her children. When Maddie attempted to make it appear as if Zach tried to attack her, Maria realized that she needed to do something drastic to bring her family back together and moved to California with Maddie to be near Hayley and Mateo. Sam followed a few months later.

Maria settled in to life in California but Pine Valley remained close to her heart. In January of 2010, Pine Valley was named the "best town in America" and Hayley's show ran a special episode about the town. Maria was asked by her sister-in-law Hayley to be a part of the show by speaking about her time in Pine Valley and she agreed.

In July of 2011, a doctor named Griffin Castillo called Maria and inquired about her experience as a patient of David Hayward's and his Project Orpheus. Griffin explained that he was trying to shut down David's experimental procedure and could use any information she could share. Maria was not able to recall much from her time with David but she told Griffin how David had lied to her for months to keep her away from her family and she was willing to help Griffin stop David.

Maria paid a quick visit to Pine Valley in September of 2011 to consult with another doctor regarding a patient. She ran in to Jake and Amanda Martin and Jake's father Joe Martin at the hospital and they briefly chatted before Maria had to return to Miami.