Jack's longest relationship is with Stuart Lamarack (Dave Foley), which lasts several months during the sixth season, until Jack cheats on Stuart.

Jack is also the owner, or former owner, of a dog (Klaus Von Puppy) and a parrot (Guapo). Since the start of season three until he moves into Karen's mansion at some point after the eighth season, Jack lives across the hall from Will and Grace, and in his spare time he operates a one-table café, Jacques, in the hallway outside his front door