At the end of Battle Tendency he married Lisa Lisa's assistant, Suzi Q and had one daughter with her, whom he was very close to. Because his daughter married a Japanese man, Joseph had a deep grudge against them, though he grew close to his grandson, Jotaru Kujo. At some point in his marriage, Joseph had an affair and had an illegitimate child named Josuke Higashikata.
Though he doesn't appear it due to his cocky attitude, Joseph is incredibly intelligent having outwitted most of the Pillar Men. He also has a kind heart which helps him make friends easily.
He is 18 to 19 years old in Battle Tendency, 69 in Stardust Crusaders and 79 in Diamond is Unbreakable. By the time of Diamond is Unbreakable, senility and frailty finally caught up to Joseph due to him neglecting his Ripple training.