Regarding his family, David McCallum was married twice. He first married actress Jill Ireland in 1957, but they divorced in 1967. She then married actor Charles Bronson. McCallum and Ireland had three sons: Paul, Jason (who was adopted and who died from an accidental drug overdose in 1989), and Valentine.

He later married Katherine Carpenter in 1967, and they have been together since. They have a son, Peter, and a daughter, Sophie. As for his private life and his assets, David McCallum has kept such details out of the public eye, which is quite common for celebrities and other public figures.