Alison Stewart's birth was unconventional to say the least. When the middle aged Susan Stewart regretted the fact that she couldn't give her younger husband, Larry, a child, her daughter Emily volunteered to donate an egg which would be fertilized and implanted into Susan. The procedure was a success and Alison was born. Though Emily wanted to be more of a mother to Alison, Susan reminded her that Alison was to be raised as her daughter. After her parents' divorce when she was still a toddler, Alison was raised by Susan.

Though Susan tried to be an attentive mother to Alison, her career kept her busy and Alison spent many hours alone. Because of this lack of supervision, Alison grew up with a major selfish streak. By the time she was a teenager, Alison's life revolved around herself and what she wanted, and the one thing she definitely wanted, at the age of 16, was Aaron Snyder. Unfortunately for Alison, Aaron wasn't interested in her; he was interested in Lucy Montgomery. Not one to let that stop her, Alison decided that she'd do whatever it took to make Aaron hers. Alison didn't really keep her manipulative nature a secret, however, and she was confronted by her sister, Emily. Resentful of Emily's well-meaning advice to forget about Aaron, Alison rejected Emily's friendship and decided to break up Aaron and Lucy by getting Lucy in trouble with her father, who disapproved of the relationship, by snapping photos of Lucy on Aaron's motorcycle. Though she tried to be clever and sneaky, the couple figured out that Alison was responsible and confronted her. Feigning regret, Alison begged the pair to forgive her and made an effort to help them in their quest to be together. At the same time, Emily decided that it was finally time that Alison learn the truth about her parentage and revealed that she was her real mother. Shocked, Alison rebelled against both Susan and Emily. Angry and confused, Alison found a friend in Aaron.

However, friendship wasn't what Alison wanted and she tried to get Aaron to fall in love with her by having him rescue her from a fire. Unfortunately, the plan backfired with Aaron being charged for the crime. Alison kept mum about her involvement but felt so guilty that she helped Aaron escape from the police with Lucy in tow. Confronted by Lucy about why she was helping Aaron, Alison broke down and confessed to her the truth. Alison was then horrified when Lucy decided to go to the police. Though she begged Lucy not to, Lucy had her mind made up but was hit by a trolley before she had a chance. In the end, Lucy wound up with amnesia and Aaron was set free when Alison's young stepbrother mistakenly confessed to the setting the blaze. Unfortunately, things didn't go as well as Alison hoped. Eventually, Will remembered that he didn't set the blaze. Knowing she'd be sent to jail, Alison tried to persuade Will to cover for her. Though a confused Will was almost willing, Dr. Chris Hughes suspected that he was covering for someone and, suspicious as to why Alison kept hanging around the hospital, he confronted her. Stressed out and feeling enormous pressure, Alison confessed all to Chris but then ran off to Chicago to avoid prosecution. Luckily, Emily and Chris were able to find Alison before any harm came to her and they brought her back home. Back at home, Alison decided to face the consequences and turned herself in to Hal, who surprisingly offered to support her because she was family.

After confessing to arson, Alison was sentenced to spend a year in a correctional facility. Though she tried to avoid jail time by feigning an illness, Susan saw through her scheme and got her released from the hospital. Alison started being threatened by her roommates and confided in Chris. When she learned that her roommates planned to attack other inmates, she alerted the authorities and was rewarded with an early release. After her release, she got a job at Memorial where she became even closer to Chris. Though he tried to deter the relationship on account of her age, it was obvious that he was as attracted to her as she was to him. While Chris was trying, not too successfully, to fight his attraction to Alison, Memorial was being rocked by a series of unexplained murders. Chris became increasingly concerned because he believed the murderer was fellow intern Dr. "Gordo" Gordon, who was also interested in Alison and who Alison was using to make Chris jealous. Also under suspicion was Dr. Ric Decker, Susan's boyfriend. Later, Bob Hughes was attacked and left comatose and Gordo wound up dead! Though Dr. Decker immediately came under suspicion, things changed when he was attacked as well. Despite this, Alison still didn't trust Ric and told Chris she thought he was the killer. In the end, Chris began to realize that Alison was right and they tried to gain access to Ric's safety deposit box in order to obtain evidence against him. Though they were caught in the act of notarizing a fake death certificate by Chris's brother, Tom, Alison made off with the fake document and gained access to the box. Unfortunately, Ric caught her in the act, kidnapped her, and attempted to murder her. Luckily, Chris found her and was relieved to learn she was still alive since she was able to replace the poisoned vial with water. By this time, Bob had recovered and named Ric as his attacker. In the end, Ric was apprehended and Chris, who ended up rescuing Susan and Alison from Ric, realized how much he loved Alison. Soon after, Chris and Alison made love.

Unfortunately, just as she was in a mature relationship, Alison let jealousy get the better of her. Jealous of Chris's closeness to his old friend, Katie Frasier, after her husband's death, Alison lied to Mike Kasnoff so that she could be alone with Chris, who was supposed to be looking after a depressed and ill Katie. Unfortunately, Katie and Mike argued and, that night, a medicated Katie left the house and accidentally hit Mike with her car. Although Mike turned out to be alright, Chris decided that perhaps Alison was too immature for him after all and ended the relationship. Distraught, Alison ended up with a equally broken-hearted Aaron (who had just had a fight with Lucy) and the pair ended up sleeping together! The next day, Alison was horrified when Chris showed up and realized that she'd been with a man, although he didn't know who it was. Later, Alison made a startling discovery--she was pregnant. Preparing to tell Chris about the pregnancy, Alison was heartbroken when he announced that he was moving to Philadelphia. Believing he wanted nothing to do with her, and not wanting to ruin his life, Alison kept quiet. When the truth came out, while Chris was away, a flustered Alison named Aaron as the father! Though she knew he wasn't, the lie was already out and Alison found no way out of the situation since she named the father in front of her mother and Chris's father. Suddenly, Chris returned to town wanting to be back with Alison. Not wanting to hurt his career, Alison confessed that Aaron was the man Chris saw her with months earlier and said that he was the father of her unborn child. However, despite Alison's assurances that this was Aaron's child, Chris wasn't totally convinced that it wasn't his baby and demanded a sonogram be done. Convinced that Chris didn't love her, Alison altered the tests to show that the baby was born later than it was. Desperate to convince Chris that her life was with Aaron, Alison impulsively convinced Aaron to marry her! However, when she saw how excited Aaron was getting at the prospect of fatherhood and all the plans he was making for their future, the guilt overcame her and Ali confessed the truth to Aaron.

Hurt and angry, Aaron was set to go to Chris with the truth, despite Alison's pleas that they keep it quiet since she feared Chris would take away her baby. Seeing Chris's judgmental attitude toward a woman who abandoned her child only strengthened Ali's resolve since she knew that Chris would have her judged an unfit mother because she had lied. Seeing Chris's condescending attitude at the hospital showed Aaron that perhaps Alison was right and he agreed to keep quiet. Very afraid that Chris would take away her baby, Alison ran off to Chicago to start a new life. At the same time, Chris learned that the baby was his! Fearing that Alison had run off to Chicago to get an abortion, Aaron ran off to find her and stop her. Relieved when he learned that she had no intention of getting an abortion, Aaron convinced her to return to Oakdale and face Chris. Unfortunately, Chris followed Aaron to Chicago in order to talk to Alison. Deathly afraid that Chris would have her declared an unfit mother, Alison ran off to the fire escape to get away. Chris followed and as she was poised on the ladder, he tried to reassure her that he had no intention of taking her baby away. Just as he was able to convince Alison to come off the ladder, and put his arm out to help her, Alison fell! It was at this point that Aaron rushed out to the roof and from his perspective, he saw Alison fall after Chris lunged at her! Tragically, the fall caused Alison to lose her baby and Aaron made sure he told everyone what he thought he saw; Chris push Alison off the roof. Later, at the hospital, a distraught Alison had no clear memory of what exactly occurred, leaving the police to believe Aaron's version of events. However, after some time, Alison's memory started to clear and she finally remembered what happened. Now exonerated, Chris professed his love for Alison and the two made plans to move in together.

Although they found a fabulous, and expensive, condo, the problem was that it was still under construction. So, needing a place to stay, they accepted Chris's parents' offer to stay with them. After a tense few months, tense because Alison's youthful impulsiveness tended to grate on Kim Hughes's nerves, the condo was finally finished. Unfortunately, it had sustained flood damage. Wanting to help Chris out so they could afford a new place, Alison suggested getting a second job at Metro, where Aaron was working. Chris however was adamantly against that idea. However, that didn't stop Alison who was determined to help Chris by saving money. Secretly getting a job as a waitress at Metro, Alison snuck around for weeks, lying to Chris about her whereabouts and what she was doing. Although she did her best to cover her tracks, she only ended up spinning a more elaborate web of lies. Finally, the truth came out but, to Alison's surprise, Chris forgave her. In addition, Chris finally tired of his mother's condescending attitude toward Ali and the pair moved out of the Hughes house and moved into Susan's. Not long after, Chris surprised Ali by proposing marriage. Although Ali was wary about whether they should take this big of a step, Chris convinced her to accept his proposal and the two made plans to marry. But the one person who couldn't support her upcoming marriage was Aaron who tried to convince Alison that was a mistake; that Chris couldn't love her for who she was.

However, all Aaron succeeded in doing was alienating Ali and she warned him that if he couldn't accept her choice, they were no longer friends. So, from that point on Aaron accepted the engagement. Unfortunately, Aaron's initial disapproval would only be the start of a series of disasters that plagued the planning of Ali's wedding. Though Ali started to be convinced that these were bad omens, Chris, though acting continually disinterested and distracted, assured her that everything would be fine and they would marry. Finally, the night of her dress rehearsal, Alison was shocked when Aaron stunned her with the revelation that he was in love with her! Shocked that he'd spring this on her the night before her wedding, Ali reacted angrily, especially when Aaron told her Chris was seeing another woman, but didn't give her a name. Ali refused to believe it and severed ties with Aaron. Unfortunately for Alison, her heart would be broken the next day when Chris, standing at the altar, told her he couldn't marry her. Her world was further shattered when she discovered that the reason Chris couldn't marry her was that he was in love with Emily! Realizing that Aaron knew the truth all along, Ali railed at him for not telling her the entire truth. Although she soon forgave Aaron, it took her longer to forgive Chris and Emily.

At about this time, Aaron had been tapped by Dusty Donovan to enter a boxing match. When Ali learned of his from Lucy, she confronted him about the dangers of boxing. However, Aaron was quickly able to assuage her fears to the point where she volunteered to help him train. In the course of the training, the pair became closer and would finally shared a kiss. Unfortunately, during the fight, Aaron would receive a near fatal blow to the head. Luckily, he survived, but was left paralyzed on his left side. His condition left Aaron disgusted and he began to resent Ali for her help. However, he quickly got over his resentment and he and Ali grew closer than ever. Soon, Aaron received good news from Dr. Ben Harris--with surgery, there was a good chance his paralysis could be corrected. Luckily, the surgery worked, and after a few months, Aaron made a complete recovery. Unfortunately, shortly after, Aaron received word that his mother was terminally ill and he rushed to Seattle to be by her side. Later that year, Aaron called Allison to ask her to come down to Seattle with him. By now, his mother's diagnosis had improved greatly and Aaron got a good job running a nightclub. After bidding her mother and sister a tearful goodbye, Alison left Oakdale.

Two years later, a meth addicted Ali was found by sister, Emily, working in Las Vegas in the adult film industry. Appalled, Emily and Dusty forced Alison to return to Oakdale get help and get a good job. A reluctant Ali got a job at Al's though spent her time trying to score drugs. It didn't take long for Dusty to realize that Alison was still using meth. Meanwhile, things had gotten so desperate for Alison that she slept with her drug dealer in order to get a hit. When Dusty and Emily found out how far she'd sunk, they decided Susan had to know and Alison had to go to rehab. However, Alison begged them to reconsider and Dusty agreed to stay with Ali while she detoxed. Unfortunately, Ali resisted. At the same time, she got a visit from her old movie producer, Lance, who ordered her to return to Vegas or he would send Susan one of her old movies. When Ali refused, Lance revealed a secret about Emily--she was a whore. Emily was forced to admit that she did work as a prostitute. Angry, Alison left with Lance after she blurted out the secret to Susan. However, her return to Vegas unnerved Alison. She definitely did not want to be there and she definitely did not want to start making porn again. When Lance tried to force her, Alison threatened him with a razor blade. Alison slashed Lance to fend him off. Luckily, Dusty came to her rescue. As he comforted a freaked out Ali, they made love.

Afterwards, Alison returned to Oakdale ready to turn her life around. When she returned who else was there but Aaron. It was clear that he and Alison parted on very bad terms--with him calling her trash. However, Aaron regretted the way things ended and wanted another chance. Alison resisted at first but then gradually let him into her life. Finally, she confessed about her recent troubles. Though she thought he'd reject her, Aaron admitted that if he would not have pushed her away in the first place she would have never been in such trouble. He then professed his love for her. Unfortunately, thanks to Lance, Aaron saw a videotape of Alison making love with Dusty. Aaron saw that as a betrayal of her sister and found that he couldn't forgive her. That same day, Emily stumbled across the tape as well and was horrified at what she saw. Later, Emily told Alison that she forgave her but she couldn't be near her for a while. Distraught, Alison was sorely tempted to use meth again, even flirting with Jesse to get some. Though she fended off Jesse's advances she did wind up with some drug paraphernalia. She was discovered by Susan who urged Ali to go to rehab. As time went by, Aaron kept misinterpreting situations which caused him to confront Alison. Convinced that he would see her as nothing but a whore, Alison walked away from him.

Soon after, Aaron struck up a friendship with a new waitress named Sofie. At the same time, Ali was renewing her friendship with Will who was now married. Unfortunately, Gwen Munson suffered a miscarriage and learned that she couldn't have children. Feeling bad for the Munsons, Alison offered to donate an egg. All she wanted was for the baby to know her role in its inception. When Aaron found out about her amazing gesture, he told her how great it was. From that point, he and Alison reconciled. Later, Aaron took pity on a pregnant Sofie and, when she found herself jobless and homeless, he let her stay at the Snyder farm. Soon, Cole's mother found Sofie and harshly accused her of getting pregnant on purpose. Aaron immediately thought Alison was to blame for Cole's mother finding out. Hurt that he would immediately suspect her, Alison called things off. As for Gwen, sadly, she miscarried the baby. Weeks later, things took an unexpected turn when Cole reunited with Sophie and convinced her that they weren't cut out to be parents just yet. Cole convinced Sophie to give the baby up for adoption. At the same time, Will's mother, Barbara, had arranged for him and Gwen to adopt a baby. Both adoptions were closed which meant that the birth mother and adoptive family would remain anonymous. Aaron knew the details of Sophie's adoption and Alison knew details from Will. After a random conversation with Aaron, it wasn't hard for Alison to figure out that the baby the Munsons were adopting must be Sophie's. Alison went undercover as a pregnant woman and approached Barbara's adoption lawyer. Finding a bootie that Sophie knitted that was going to the adoptive mother, Alison knew she was right. As Alison went to Gwen and Will with her suspicion, Sophie finally went into labor and gave birth to a baby girl. When Gwen learned that her mother and Cole had been party to selling his own baby, she was disgusted. Cole abandoned Sophie the minute he learned he wouldn't be getting any money. Alone, Sophie decided to let the Munsons adopt her baby after all. Gwen named the baby Hallie Jennifer and chose Aaron and Alison to be her godparents.

Months later, Alison found herself in Chris's orbit again. Soon, the pair resumed their friendship to Aaron's dismay since he did not trust Chris. Despite Aaron's concerns, Alison insisted that Chris was a good guy. Soon things between Alison and Chris started to get romantic but, although she wanted to go to bed with him, at the last moment she backed out out of fear. Chris was amazingly gentle and assured Alison that there was no pressure. He also accepted it when Alison confided in him about her troubled past. At the same time, Chris noticed the excellent work that Alison was doing at the hospital and convinced her that she should be a nurse. Alison quickly warmed up to the idea and entered the nursing program. The course work was overwhelming and Ali later confided in Aaron that she decided not to pursue anything romantic with Chris. She wanted to concentrate on her studies. Though Alison almost flunked out as soon as she started when she missed her first test, thanks to Chris, she was given a make-up exam. Meanwhile, Alison, again, unexpectedly backed off from having sex with Chris. Not long after, she informed him that she only wanted to remain friends, stating that she wanted to concentrate on her studies. Upset, Chris threw Alison's porn star past in her face. In the midst of this, Alison continued to confide in Aaron, even sharing her elation when she passed (barely) her lab work. Unfortunately, the very day that Chris found Alison at the Snyder farm and mistakenly accused her of sleeping with Aaron, Alison was kicked out of the nursing program. Believing that Chris used his influence to get Alison kicked out of the program, Aaron convinced Ali that she should sue for sexual harassment. Alison did but, unfortunately, she lost the case when Chris lied on the stand that, Alison was reluctant until Chris asked that Alison be removed from patient care. Though Chris and Tom, acting as Chris's lawyer, warned Alison that things could get ugly and her past could come out, Alison pressed on with the lawsuit. Unfortunately, Alison lost when Chris lied tht on the day of Alison's dismissal, he told the head of the nursing program that he believed that she'd be a good nurse.

Not long after, Chris admitted that he'd lied and Alison was re-admitted into the nursing program. Soon after, Alison received a present in the mail that she believed came from her father. It was a bracelet. Immediately after putting on the bracelet, Alison began acting erratically by lashing out at Aaron for no reason. Alison's behavior became more and more erratic and eventually led her to try to commit suicide in the Snyder pond. Luckily, Chris saved her but Alison had no memory of what happened. Though Aaron was convinced that Chris had tried to hurt her, Alison was unconvinced. Soon an unidentified toxin was found in Alison's blood and Chris made it his mission to find out what it was. Unfortunately, Chris was behaving erratically himself—first by stripping off his clothes to control a persistent itch and finally by attacking Aaron. The unidentified toxin was found in Chris's blood as well and Bob was worried that there was a virus at work and quarantined the hospital. When Chris's mother mentioned that the new watch he thought she sent him was not from her, he became suspicious and analyzed it—the watch was laced with the toxin! Chris quickly figured out that Alison was poisoned too by bracelet and Emily was poisoned by her perfume. It didn't take Chris long to figure out who was responsible—Rick Decker! Knowing that Decker, under guard, was at Memorial trying to find an antidote to the poison, Chris figured out that Rick was the one responsible. Finally, things came to a head with Decker taking an unconscious Alison hostage. Luckily, Chris was able to rescue Alison from Rick and developed an antidote to the poison, saving Alison from death. Days later, Aaron proposed marriage and although she was uncertain, Alison accepted. Though Aaron wanted to wait a year so they could have a proper wedding, Alison surprised him by suggesting that they marry immediately. Unfortunately, things would end badly when Chris informed Aaron that he and Alison slept together the day before their wedding. Upset, Aaron promptly divorced Alison and left town while Chris left town as well.

Afterward, Alison began an unexpected relationship with Casey Hughes, Chris's nephew. She also began a friendship with a young man named Hunter who worked for Emily. Alison formed an immediate bond with Hunter who was obviously smitten with her. When Alison was honored with a nursing student award, Hunter decided to surprise her by inviting her father. Larry's unexpected appearance at the dinner shocked Emily, Alison, and Susan. Despite Alison's initial reaction, which was to tell her father that she didn't want to talk to him, Alison relented and let Larry try to explain his years of absence from her life. Meanwhile, Emily was thinking about having a baby on her own, using the eggs that were harvested when Alison was conceived. The problem was, the eggs were no longer at Memorial Hospital. Though Larry denied any knowledge, it was soon discovered that he had the eggs transferred to a facility in Chicago and had some implanted into his lover at the time—Aurora Hunter who desperately wanted a child. Aurora was none other than Hunter's mother which made Hunter Alison's brother. With this startling revelation, a shamed Larry departed Oakdale. Unable to deal with his romantic feelings toward his own sister, Hunter left town as well.

Months later, Alison met a researcher named Mick Dante who was trying to peddle a revolutionary new product to Emily. Mick touted the product as a fountain of youth that would ultimately allow Emily to get pregnant again. Both Alison and Paul were skeptical and investigated Mick. When Alison discovered Mick passed out from another nosebleed, she threatened to tell Paul and Emily about it, if Mick didn't get some help. Mick insisted that there was no diagnosis or treatment for his aliment. He said he had two forces inside him, battling each other for control. Despite her new engagement to Casey, Alison could not resist Mick who she saw as a tortured man. However, Alison was determined not to repeat past mistakes and broke off all contact with Mick. Unfortunately, Mick and Alison's unhealthy obsessions with each other bubbled out of control, and they had sex in the bell tower. Later, Mick confessed to Alison that James Stenbeck brainwashed him into doing his bidding. Tough he knew it wasn't possible, a part of him believed that he was James Stenbeck. Casey and Alison's relationship fell apart when Mick, under James's control, crashed Alison's wedding. Mick took the guests hostage and revealed that he'd slept with Alison. Alison convinced Mick to flee with her, but once he returned to himself, he asked that she go with him only of her own volition. Mick trained a gun on Casey, and Margo drew her weapon on Mick, who suddenly flung himself in front of a passing car. Mick regained consciousness and claimed to Alison that she'd exorcized his James demon. Alison wheeled him to the hospital roof for fresh air, but Casey accused them of escaping. After a dangerous confrontation with Casey, Mick fled, but later turned himself in.

Soon after, Chris returned to town. Though Chris wanted to rekindle their relationship, Alison felt that too much damage had been done. At the same time, Casey embarked on a relationship with Vienna Hyatt. However, Alison didn't trust Vienna not to hurt Casey and warned him that getting involved with her was a mistake. Alison turned out to be correct. Realizing that Alison was the woman he loved, Casey asked her to marry him and move to Carbondale, where he intended to enroll in law school. She also shared her dream of eventually becoming a doctor. With her tortured past behind her, Alison went off with Casey for a bright future.