In France from 1947, Karmitz entered the film industry as an assistant to directors such as Jean-Luc Godard and Agnes Varda before setting up MK Productions in 1963. He made his directorial debut in 1967 with "Sept jours ailleurs" and followed it, much affected by the events of May '68, with the militantly leftist, "Comrades" (1970) and "Blow for Blow" (1972).

Subsequently ostracized by the French film industry, Karmitz turned to exhibition and distribution, helping to promote works by young, unknown and/or otherwise marginalized directors including Wim Wenders and Marco Bellocchio. Under the MK2 banner, he has produced an impressive list of films, including Godard's "Every Man for Himself" (1980), Louis Malle's "Au Revoir, les enfants" (1987), and a series of features by Claude Chabrol which revitalized the director's career.