Though not her biological child, Monica Quartermaine always favored Jason, who was everything that his brother A.J was not: sweet, kind, loving, nonmanipulative, and sober. Before he went from Quartermaine to Morgan, Jason had dreams of following in Monica's and Alan's footsteps and becoming a doctor.
One night, a drunken A.J., despite Jason's efforts, decided to go for a drive. Concerned, Jason jumped into the car with him. Inside the guest house, Ned Ashton heard a loud crash. Rushing out, he saw the car totaled, and A.J. unconscious at the wheel. Looking around, he then spotted Jason, who had been thrown from the car and was unconscious in the snow. A.J. regained consciousness, and Ned realized that his cousin was drunk.
Ned dragged A.J. back to the guest house, called for an ambulance, and then summoned Reginald the butler in the main house. Ned asked Reginald to get A.J. upstairs and to make sure that he didn't talk to anyone. Ned then ran out and sat with Jason's body until the ambulance arrived.
In order to keep Monica and Alan from further devastation, Ned claimed to have been the driver. This only increased A.J.'s feelings of guilt. Eventually, the truth emerged.
Bad Boy Jason Morgan
After the accident, Jason changed completely. He became cold and seemingly without any emotional attachments. He decided against becoming a doctor and went to work for Sonny Corinthos. He also changed his name to Jason Morgan, Morgan being his paternal grandmother Lila's maiden name.
Alan and Monica watched in horror as Jason Morgan became a mob enforcer and seemed not to remember any feelings that he had for them.
Since then, Jason has softened toward his family, embracing Emily as his sister and paying attention to Monica and Alan before Alan passed away.
However, Jason remains Sonny's enforcer, and Jason Quartermaine has vanished forever.