Delvaux studied German language and law at the Free University in Bruxelles, as well as piano at the Belgium Royal Conservatory. During 1950, he became interested in film while playing piano at silent films screenings. He later became the manager of a film educational program for Belgium teachers. He also organized a seminar about film language for the sociological department of his university. He began his directing career with documentaries for television, such as the TV series Fellini (1960). Besides Fellini’s biography, he also made a biographical TV series about a French director, Jean Rouch (1962), a TV series about the Polish film industry Cinéma polonais (1964) and the documentary film about Woody Allen To Woody Allen from Europe with Love (1980). He made his feature film debut with Der man die zijn haar kort liet knippen (One Night... a Train, 1965), for which he also wrote the screenplay. He later directed and wrote screenplays for his films Un soir, un train (One Night... a Train, 1968), Rendez-vous ŕ Bray (1971), Een vrouw tussen hond en wolf (1979), Benvenuta (1983) and L\' oeuvre au noir (1988).