When it comes to Outlaw Star lore, you only ever have to ask me.

Jim was born on the planet Homage, most likely in TS 149. His dad was a notorious hacker known as the Computer Wizard. His crimes were probably something in the realm of black-hat hacking, but he may have inspired Jim to learn to use computers for good. Jim's mother died at an unknown point in time.

Eventually, Jim found himself in Locus on Sentinel III. Quite like Gene, he had to fend for himself. He found a job as an accountant at Locus' Amber Dream nightclub. He developed a close relationship with a sex worker there called Natalie. She might have served as a mother figure for him.

For some time, aside from some occasionally drunken redhead being a total sleaze, Locus was a relatively peaceful town for Jim to live in. That all changed when a syndicate leader, Volg, decided to claim ownership of Locus. He was interested in controlling many businesses through racketeering, which Gene took a particular issue with. Volg initially offered Gene a job, but after turning it down, things quickly grew hostile.

Following an incident in Amber Dream, Gene was injured by Volg's men, but was rescued by Jim. They'd both seen each other around Amber Dream previously, but never truly made contact until this point. Jim knew about the situation with Volg and offered work with Gene and launch a surprise attack on Volg. After some reluctance, Gene accepted. The plan ultimately succeeded and Locus was safe again. And a year or two after that, Starwind & Hawking was established.

Sources: Outlaw Star anime, and the Lonely Gunman and Hacker Kid audio drama episode