He was married to the actress Shirley Douglas from 1966 until 1970, daughter of Canadian democratic socialist statesman Tommy Douglas by whom he has a daughter Rachel and a son Kiefer Sutherland (also a well-known actor). He was previously married to Lois Hardwick (1959 - 1966) (divorced), and briefly had a relationship with the actress Jane Fonda during the early 1970s.
He met his current wife, the French-Canadian actress Francine Racette on the set of the Canadian pioneer drama Alien Thunder (1974) (she was later to star in the classic World War II drama Au revoir les enfants (1987).