A.J. was always a troubled child who grew up to develop a drinking problem that led to many poor choices and failed relationships. As a student at Port Charles University, he began running a loan shark operation and was arrested for drunk driving for the first time. He was also caught up in a scandalous affair with an older woman named Nancy Eckert, which led Lila, his beloved grandmother, cutting off his inheritance. A.J. was forced to go to work as an orderly at General Hospital.
In 1992, A.J. was arrested two more times for drunk driving. The first time, Alan left him in jail overnight, hoping it would teach him a lesson, but it didn't. The second time, A.J.'s girlfriend, Nikki Langton, told the police that she had been behind the wheel of the car. A.J. and Nikki planned to marry, but Alan paid Nikki to leave town.
In 1993, A.J. took a job as a desk clerk at the Port Charles Hotel, which was owned by his cousin, Ned Ashton. Before long, A.J. was engaged in a torrid affair with Ned's lover, Julia Barrett, who sold her shares in the hotel to her boy-toy before leaving town.
In 1995, A.J was in a car accident with Alan while driving drunk. A year later he was in a wreck with Jason that left Jason with brain damage. Initially, Ned took the blame for the accident to protect the family, but A.J. eventually confessed the truth to his family.
A.J. moved out of the Quartermaine mansion and into an apartment across the hall from co-worker and friend, Carly Roberts. Carly was living with Tony Jones, who had left his wife for Carly. One night, Carly and A.J. got drunk and had sex. Afterwards, A.J. didn't have any memory of what happened, but he decided to stop drinking and focus on making things work out with his girlfriend, Kiesha Ward.
When Carly discovered that she was pregnant with A.J.'s baby, she decided to keep the truth to herself, so that Tony Jones would marry her. Carly schemed to push A.J. off of the wagon by drugging him, dumping him in the back alley, dousing him with booze, and then arranging for his parents to find him. By the time Carly delivered a baby boy, the A.J. had remembered everything and Tony had discovered the truth about Carly's affair.
Desperate to keep custody of her baby, Carly claimed that the baby's real father was Jason Morgan, A.J.'s brother. The lie worked until Robin, Jason's girlfriend, decided that A.J. had the right to know that he was a father. When A.J. found out the truth about Michael, A.J. married Carly and they shared custody of Michael with Jason. A.J. was then appointed CEO of ELQ.
Continuing to be insecure about his abilities as an executive and husband, A.J. constantly suspected Carly of cheating with Jason. Carly did carry on an affair with Jason, but one night she spotted him in Kelly's with young Elizabeth Webber. Carly jumped to the wrong conclusion about Jason and Elizabeth, so she stormed over to Sonny's penthouse. Sonny was Jason's boss and best friend. Carly wanted to know what was going on between Jason and Elizabeth, but during the heated confrontation Carly and Sonny ended up sleeping together.
When A.J. learned that Carly was pregnant, he assumed that is was Jason's baby. A.J. agreed to pass the baby off as his because he thought that it was what Jason deserved after Jason had stolen A.J.'s son, Michael. However, Sonny got wind of Carly's pregnancy, so he barged into a Q family gathering to stake claim to the baby. Carly moved out of the mansion, but returned one night where she encountered a drunken A.J. on the staircase.
Carly and A.J. argued. When A.J. reached out to Carly, she jerked away and then stumbled down the stairs just as Sonny walked in. Carly was rushed to the hospital, but it was too late; she had suffered a miscarriage. Sonny and Carly blamed A.J. for the loss of their child, so they took steps to cut A.J. out of Michael's life.
A.J. found himself once again disinherited by his family and tossed out of the mansion. Meanwhile, Sonny arranged to have A.J. kidnapped. A.J. was suspended from a meat hook and threatened with death until he relinquished all rights to his son. Afterwards, Sonny adopted Michael and then renamed him Michael Corinthos III.
Self-destructive to the extreme, A.J. continued drinking and began devising ways to squander his money. He shamelessly pursued Hannah Scott, the only person who seemed to care about him, even though she was dating Marcus Taggert. One day she found him in his hotel room, unconscious. He woke up in the hospital and learned he had almost died of alcohol poisoning. Hannah and his family begged him to go to rehab, but he refused and chose to quit on his own.
Hannah started falling for A.J., so she broke off her relationship with Marcus. She attended Winterfest as A.J.'s date, but only weeks later, she left town on a secret assignment, saying goodbye to him without a great deal of warmth.
A health scare for Monica made A.J. realize how important family was, so he moved back into the mansion. A.J. banded with Ned to protect Emily from Edward's tyranny. A.J. also started to take steps to reclaim Michael. A.J. received support from an unexpected source: his long-lost sibling, Skye, a kindred spirit who had battled alcoholism and other personal demons. Though he originally blackmailed her into helping him fight Carly and Sonny for custody of Michael, the scheme was abandoned because of their genuine empathy for each other, and Skye's hatred of Sonny. The black sheep brother and sister became friends, confidantes, and co-conspirators.
In January 2002, A.J. began pursuing Courtney Matthews, Sonny's newfound sibling. It wasn't love that drove him-he was selling the young woman the ultimate "Pretty Woman" fantasy as part of a plot to drive Sonny crazy and to get his son Michael back. A.J. even went so far as to marry Courtney. When Sonny found out, he nearly killed A.J. Thinking he finally had Sonny where he wanted him, A.J. proposed a deal: if Sonny gave Michael back to A.J., then A.J. would divorce Courtney, but Sonny rejected A.J.'s offer.
As time passed, A.J. realized that he had fallen in love with Courtney. When his mother called Courtney trash and slapped her, A.J. and Courtney moved out of the Q mansion. They found a dumpy apartment, but they were happy. Edward threatened to cut-off access to the Quartermaine fortune if A.J. didn't keep trying to regain custody of Michael, A.J. refused to use Courtney, so Edward followed through on the threat.
A.J. tried to live on the straight-and-narrow, but Sonny had ordered Jason to keep an eye on Courtney. It wasn't long before A.J.'s insecurities about Jason resurfaced. A.J. started drinking again. One night, A.J. drove drunk right into the strip club called the Oasis. Wanting to protect her husband, Courtney made a secret deal with the owner to become a stripper in exchange for the owner's silence regarding A.J.'s guilt in the accident.
Regretting his actions, A.J. tried to make it on his own and even got a job as a forklift driver to support his bride. However, when A.J. managed to tell Michael what Sonny did for a living, Sonny retaliated by taking A.J. to the Oasis and showing him what his wife was up to. Humiliated and angry, A.J. burned down the Oasis, but Courtney begged Jason to cover up A.J.'s guilt.
Wanting his wife to lean on him more, A.J. hired the former owner of the Oasis to stalk Courtney, while A.J. was supposedly out of town looking for work. Courtney didn't want to worry A.J., so she turned to Jason for help. Jason and Courtney grew closer, but tried to fight their attraction until they discovered that A.J. had hired Coleman to terrorize Courtney.
Courtney was furious, so she tossed A.J. out and then took steps to end their marriage. A.J. tried to get Courtney back and even got a job from Ned at ELQ, but Courtney had already moved on with Jason. A.J. blamed Jason for his situation with Courtney, so A.J. retaliated by trying to frame Jason for Luis Alcazar's murder. A.J. enlisted Skye's help; she had her own fish to fry:Brenda.
A.J. and Skye hired a fake witness, but Courtney got wind of what was going on. Courtney pulled a gun on A.J. to get him to confess to his misdeeds. However, it was all moot when the real killer was revealed to be Alexis Davis.
After the charges were dropped against Jason and Brenda, A.J. tried various tactics to get Michael back. A.J. got in one last dig at Courtney when he invited her stripper friends to her bridal shower and paid her mother to try to persuade Courtney not to marry Jason.
A.J. rallied around Emily, along with the rest of the family, when it was revealed that Emily had breast cancer. Shortly after Emily returned from the brink of death, A.J. went back to his plans to take over at ELQ. He got his chance to become CEO when Ned was falsely accused of rape.
A.J. got his hands on four of the five cards in the Dead Man's Hand, which had been the actual cards held by Wild Bill Hickok at the time of his death. A.J. stole the cards from John Jacks, who believed them to be his lucky charm. He tried to find the last card, which was continually being passed back and forth between Jasper Jacks and newcomer Samantha McCall. More people wanted the cards than A.J. anticipated, so the ones A.J. had ended up stolen from him.
A.J. tried to get the cards back at Luke's secret auction, but A.J. had been outbid. A.J. decided to return to running ELQ, which he did so poorly that he left the company wide open for a corporate raid. Tired of the constant criticism from his family and the lack of love and praise, A.J. exacted his revenge. He emptied their bank accounts and then took off into the sunset with Lydia Karenin, Nikolas Cassadine's wife.
A.J. resurfaced in 2005 as the mastermind behind the plot for Faith Roscoe to kidnap Sonny's children. A.J.'s plan had been to stage Michael's death, so that A.J. could spirit him away and raise him without interference from Sonny, Carly, and Jason. A.J. had allowed everyone in Port Charles to believe that Michael had been killed. Instead of riding off into the sunset with his son, A.J. decided to return to Port Charles where he hid out in the attic at the Quartermaine mansion. Alan discovered his son and grandson, so he agreed to help them. However, it soon became clear to Alan that A.J. wasn't thinking rationally.
Things reached a climax when Jason tracked A.J. down at the mansion. After A.J. shot Alan in the back, A.J. and Jason fought on the second floor of the mansion until both men went tumbling down the staircase. A.J. ended up in the hospital with a broken back and, hours later, was suffocated by Dr. Asher Thomas. After A.J.'s death it was revealed that years earlier, A.J. had hired Dr. Thomas to kill Jason. A.J. had been under the belief that Jason would be in a persistent vegetative state from the head injuries that Jason had suffered in the accident that A.J. had caused.
Dr. Thomas killed A.J. because A.J. had tried to blackmail Dr. Thomas into certifying that A.J. had been insane at the time of Michael's kidnapping and Alan's shooting.
In October of 2012, A.J. was revealed to be alive after Monica contacted him and shared the news that Jason was presumed dead. A.J. returned to Port Charles to comfort Monica over the loss of her other son and Monica shared how she had allowed everyone, even Alan, to believe that A.J. was dead after Dr. Thomas had tried to suffocate him. A.J. thanked Monica for helping him avoid time in prison and she thanked him for his visit but advised him to leave town immediately before anyone else learned he was alive so he would not be sent to prison for shooting Alan.
A.J. decided he needed to see Michael and vowed to find a way to avoid prison while he forged a relationship with his son. A.J. revealed himself to Michael and tried to explain that he was not the horrible person that Sonny and Carly had made him out to be. Michael refused to believe what A.J. had to say and he walked away. Meanwhile, Carly and Tracy learned that A.J. was alive despite Monica's attempts to convince them otherwise. Michael arrived as Carly confronted A.J. and threatened to call the police. To A.J.'s surprise, Michael defended A.J. and begged Carly not to turn him in. She ignored Michael's wishes and A.J. was taken into police custody.
Michael remained with A.J. at the police station until he was released on bail. A.J. was enraged to learn that Michael had been shot in the head and had served time in prison and he blamed Carly and Sonny for all that his son had been through. After A.J. made bail, he believed that he had made progress with Michael and the two bonded more when Edward passed away.
Edward's death brought A.J.'s adopted sister and constant ally Skye back to town. She encouraged A.J. to not only fight for his son but also his place within the family business. A.J. and Skye were among Edward's beneficiaries of ELQ stock and they realized that A.J. could oust Tracy at the helm of ELQ if they convinced Jason's widow to vote against Tracy. A.J. reminded Skye that he needed to beat the charges against him first. He received some positive news in his case when his attorney, Diane Miller, informed him that he might be able to go free if was able to supply information about a higher profile criminal. A.J. announced that he could and produced a picture presumed deceased international criminal Cesar Faison that he had taken while he was at a clinic in Lucerne, Switzerland.
The information that A.J. provided about Faison was enough to garner his freedom. He immediately worked on his plans to obtain control of ELQ and he planned to have Michael by his side. A.J. tried to win Michael over by making Sonny look bad but he changed his strategy after Michael realized what A.J. was up to. Instead, A.J. made inroads with his son though their work at ELQ. The father/son team worked together and successfully ousted Tracy from ELQ. However, their victory was short-lived after an incriminating article about ELQ was published and the company faced both legal and financial threats.
A.J., Michael, and their new employee Duke Lavery decided the best way to save ELQ was to bring back the Pickle Lila relish that had saved ELQ in the past. While they worked to obtain the last bottle of the relish from Tracy, A.J. experienced a few bouts of panic attacks. Elizabeth Webber was present during one of them and he credited her with saving his life. A friendship developed between Elizabeth and A.J. and he followed her recommendation to see a therapist regarding the panic attacks. In return, he supported her when he brother underwent an emergency surgery and later asked her out on a date.
A.J. escorted Elizabeth to the Nurses Ball but their new relationship hit a snag soon after when A.J. accused Elizabeth of sleeping with her former lover Nikolas Cassadine. Elizabeth told A.J. that she was done with him and he had a one-night stand with Carly, which he regretted immediately. Elizabeth did not know that A.J. had slept with Carly and she agreed to give him another chance.