Unlikely hero extraordinaire, Jack was a medical examiner before gaining his powers. Now, he's the boss of JS Consulting and working with the NYPD SCU. With his keen eyes and methodical approach to crime, he's the closest thing Professionals has to the classical "upstanding cop" archetype. Although he has a bit more relaxed attitude towards the law due to his exposure to the team, he has a rigid set of morals that he will not compromise. Jack is haunted by the memories of his girlfriend Susan, whom he was forced to kill in the line of duty in Late Goodbye. Since then, he's been in a relationship with Chrome.
Despite everything he's been through, Jack is probably the most "normal" main character in the multiverse.