John "Jagger" Cates arrived in Port Charles in 1992. He and some other gang members broke into Kelly's Dinner one night and beat up Ruby Anderson. Jagger was shot at by police as he tried to flee. Jagger and his two younger siblings, Michael "Stone" and Gina Cates, lived on the streets, since they were orphaned. Ruby offered Jagger a job and a place to live, which Jagger accepted.

Soon, Jagger became involved with a young girl named Karen Wexler, who worked at a teen crisis hotline with fellow students Robin Scorpio and Jason Quartermaine. Karen was close to Jason, but she found herself drawn to Jagger, the bad boy with a big heart who dropped out of high school.

After a storm, Jagger, Jason, and Karen found themselves stranded on an island with escaped convicts Cal and Joseph Atkins. When Cal kidnapped Karen and dragged her to the top of a cliff, where he tried to rape her, Jagger rescued her, and Jason arrived just in time to see Cal fall to his death. The teens decided to make a pact not to reveal what had happened, but unbeknownst to them, Cal was still alive and in the care of his brother Joseph. They followed the teens back home, which resulted in a shootout. Jagger was wounded, and Cal was arrested. Unfortunately, he managed to escape and took refuge with nurse Bobbie Spencer, whom he'd befriended while in jail when they'd exchanged letters. He was once again arrested after he took Bobbie hostage and tried to rape her, then escaped in a helicopter flown by Mac Scorpio.

After Jagger decided to go back to high school, he met Brenda Barrett, also a problem child. Brenda was immediately smitten with Jagger. Jealous over Jagger's obvious attraction to Karen Wexler, Brenda instantly despised her. On the surface, Brenda and Jagger had more in common with each other than he and Karen. Brenda and Jagger both detested school, and both had a penchant for trouble. Brenda pursued Jagger until one night, they ended up making love. Their relationship was on shaky ground, and Brenda knew it. Despite having slept with Brenda, Jagger was falling in love with Karen. Karen, meanwhile, was wrestling with her own demons when long-suppressed memories of a childhood molestation began surfacing.

After Jagger found his sister, Gina, he decided to hire Felicia and Mac to find his younger brother. One night at a party, someone slipped a date rape drug into Karen's drink. The 16-year-old boy who came to her rescue was revealed to be Michael "Stone" Cates, Jagger's long-lost brother. Feeling vulnerable and somewhat unworthy of Jagger, who was by now boxing for Marco Dane, Karen decided to break off her relationship with Jagger. Hurt, Jagger turned to Brenda Barrett for comfort.

Karen's life went from bad to worse when she started living a double life. Secretly, Karen turned to drugs and began stripping at the Paradise Lounge, owned by Sonny Corinthos, her new lover. Jagger reunited with his brother Stone, who happened to be living in Sonny's apartment above the club. One night, after an argument about Stone going back to school, Jagger followed Stone home and discovered Karen stripping. Later, he discovered Karen and Sonny together, sparking a heated confrontation in which he beat Sonny up. Furious, Sonny put a hit out on Jagger's life, but Marco Dane stepped in to make a deal: Sonny would cancel the hit in exchange for a piece of the money Jagger earned as a boxer.

One night, Brenda Barrett sneaked into the Paradise Lounge and saw a very high Karen strip. Brenda wasted no time letting everyone at school know the shocking secret about Karen. It was the catalyst that motivated Karen through recovery as her friends and family supported her. Sonny, meanwhile, was exploiting his position as Jagger's boss. He ordered Jagger to take a dive in a boxing match, which Jagger refused to do. Instead, Jagger and Karen ran away and ended up making love for the first time.

In 1994, things improved greatly for Jagger and Karen. Stone and Jagger grew closer and finally had a close brotherly relationship, and Jagger quit boxing and decided to become a police officer. Karen received a college scholarship to study medicine, and she and Jagger became engaged. Unfortunately, before their wedding, a suicidal mental patient nearly killed Karen when he almost leaped from a window with Karen. Orderly Miguel Morez saved both their lives.

When Stone was determined to stop his brother Stone from driving the getaway car for escaped convict Frank Smith, Jagger stopped him but ended up crashing his motorcycle. When he woke up, he married Karen in a touching ceremony. Karen also learned that day that Scott Baldwin was her biological father. Happily married and hopeful about her relationship with her newfound father, Karen and Jagger rode out of town on a motorcycle, eager to start their new life in California.

Jagger returned to Port Charles to visit his brother after tests revealed that Stone was HIV positive and suffering from AIDS. A few months after Jagger's visit, Stone passed away with his love, Robin Scorpio, at his side.

Jagger's marriage to Karen was on shaky ground when she returned to Port Charles in 1997 to work at General Hospital while Jagger stayed in San Francisco, where he was working as a police officer. Karen began having feelings for a childhood friend, Joe Scanlon, and returned to San Francisco to save her marriage. She discovered that Jagger had been having an affair while she'd been in Port Charles. Their marriage ended in divorce, and later, Karen tragically died on the operating table after being struck by a car.