Jason Morgan is the illegitimate son of Alan Quartermaine and Susan Moore, who was murdered. Originally, he was known as Jason Quartermaine; later on, he changed his name. After Susan's death, the baby was moved into the Quartermaine mansion. Monica became very devoted to Alan's second son.
A Quartermaine by Birth
Jason went to boarding school and came home to Port Charles in 1991, intending to become a doctor like his parents.
Jason's "luck" in love manifested early. He was involved with Karen Wexler, who loved Jagger Cates. He later fell for Keesha Ward, but tragedy struck. With a drunk A.J. at the wheel, there was a terrible accident. Jason suffered brain damage and remembered nothing of the Quartermaines or Keesha. He rejected everyone, opting to work for Sonny Corinthos, a Port Charles mobster. A high school classmate, Robin Scorpio, was successful in befriending him, and the two fell in love. Robin didn't know that Jason had met Carly Roberts and was sleeping with her; eventually, he broke up with Carly.
Jason Cares for Michael
Sonny Corinthos fled town and left his long-time girlfriend, Brenda Barrett, waiting at the altar. Jason took over Sonny's organization. Carly, meanwhile, was pregnant by A.J. and was now with her mother's husband, Tony Jones. They broke up; he knew he wasn't the father. She told everyone that the child was Jason's, who played along. After she gave birth, Carly, suffering from post-partum depression, left Port Charles and put Michael into Jason's care. Robin wanted Jason to tell A.J. the truth, but Jason kept his promise to Carly. He formed a deep bond with the baby and had him baptized and named Michael, after Sonny.
Carly returned and moved in with Jason. A crazed Tony Jones kidnapped Michael and Robin. Jason broke Tony's hand during the rescue and ended Tony's surgical career. During Tony's trial, Carly shot him, but he survived. Carly was sent to Shadybrook. Robin, Jason and Michael moved into Brenda's old cottage and became a family. Jason arranged for Carly to be released, and she moved in with them as well. It was a disaster. Robin left for Paris but made sure that A.J. knew Michael was his before she did.
Jason and Elizabeth Spencer
A.J. wanted custody, but it was decided that he share custody with Carly, so Carly married him. Carly decided to leave A.J. for Jason, but when she misunderstood his relationship with Elizabeth Webber, she drifted to Sonny.
Jason was hurt, literally and figuratively, shot in an ambush by a rival mobster. Elizabeth cared for him in Lucky's boxcar and later in her studio. They became close. When Elizabeth's studio was nearly bombed, Jason left Port Charles so those he cared about would be safe. He returned to help find his sister Emily when she was kidnapped, and at that time, made his peace with Sonny's and Carly's relationship.
Jason returned again in 2001 to bring down a mob boss named Sorel and hid out in Elizabeth's place. The two fell in love, but she she finally chose Lucky. Jason split again, but a year later, returned to Port Charles and Elizabeth. By now, Sonny's sister Courtney was married to A.J. and working as a stripper. Jason got her out of the club, and ultimately they fell in love. Elizabeth had broken up with him.
Jason Helps Brenda Barrett
After the murder of Luis Alcazar, Jason was arrested. He married Sonny's ex-girlfriend Brenda so they could not be compelled to testify against one another. The charges against him were later dropped, and they annulled their marriage. Courtney and Jason became engaged. Sonny disapproved but finally relented. On their wedding day, Carly, who was pregnant, was kidnapped by Ric Lansing. Later, Luis Alcazar's brother, Lorenzo, kidnapped her. Jason and Sonny had to run drugs to keep her safe. During this time, Courtney became pregnant but didn't tell Jason.
Carly was rescued in South America, and Courtney followed. She was caught and held hostage; he traded Carly for her. Courtney escaped and miscarried. She finally told Jason. They married in France but both were caught up in Sonny's and Carly's drama. Carly went into a coma after Sonny shot her (he was aiming at Lorenzo, who was trying to help Carly give birth to Morgan). Courtney took over care of the children. She became disillusioned with Jason's life of violence, and they separated. She began to see a policeman from a neighboring town, Brian. They were just friends; Brian was after Sonny. Courtney and Jason had a brief reconciliation but ultimately divorced.
Jason and Sam McCall
Jason cared for Sonny's ex-girlfriend Sam when she became pregnant. She moved in with him and they, too, fell in love. Sonny's daughter with Alexis. Kristina, developed leukemia. Sam was asked to have labor induced a week early so that her baby's stem cells could be used to help Kristina. Sam refused, but she went into premature labor. Her baby girl died as the placenta separated from the wall and the baby lost oxygen. Jason was able to hold her. It was an unforeseen complication of the pregnancy and not due to Sam's stress, and Jason tried to emphasize that to her.
After a series of events, including A.J.'s death, Jason began to have severe headaches and memory lapses. He took experimental drugs, which worsened his condition. Sam called Robin Scorpio in Paris, as she was doing research in the field. However, Jason needed surgery. Robin had Dr. Patrick Drake do the surgery at GH, saving Jason.
After Sam was in danger and comatose, Jason broke off their relationship for her own protection. In frustration, Sam had sex with her mother's husband, Ric Lansing. Jason wound up turning to Elizabeth. Elizabeth returned to her drug-addicted husband Lucky, and Jason and Sam tried again.