Jack was born in 2369 on the Federation Colony Ajilon Prime. His family was killed when the Klingons occupied the colony. Jack bounced around in orphanages until he was an adult. Jack graduated to adulthood. He didn’t have a trade, but he was highly intelligent and cunning. Jack didn’t have many options. He enlisted in Starfleet. Jack did his four years in Starfleet without any major incidents. When he left, he was equipped with the skills to be an effective mercenary and an undergraduate degree in business. Through a series of extra-legal jobs, Jack found his way to Stardust City and worked his way up from enforcer to boss.
Everybody calls him Hammer. If you need someone or something broken, you called the Hammer. He usually finds out what it was he wants to know. However, whoever or whatever had what he wanted did not fare so well. Word got around Stardust City fast, if the Hammer is looking for you, you'd either better run or show up and give him what he wanted. If you run, you might get away, you might also end up floating in the harbor, usually the next time anyone would hear about you would be on an autopsy report.