Debucourt began his career in theatre, making his professional debut in 1912. He quickly established himself as a talented stage actor and was admitted to the prestigious Comédie-Française in 1936, becoming a sociétaire (full member) in 1947. At the Comédie-Française, he performed a wide range of classical and modern roles, often excelling in characters requiring intelligence, refinement, and a subtle command of language. He also directed several plays for the institution, including works by Molière, Racine, and Corneille.
His film career began in the silent era, but he gained significant prominence with the advent of sound cinema. Over his career, Debucourt appeared in more than 100 films, often cast in supporting roles as sophisticated gentlemen, intellectuals, aristocrats, or figures of authority, sometimes with a touch of cynicism or menace. Notable film appearances include Jean Grémillon's Remorques (1941), Robert Bresson's Les Dames du Bois de Boulogne (1945), Jean-Pierre Melville's Le Silence de la mer (1949), where he played the German officer Werner von Ebrennac, Claude Autant-Lara's Le Diable au corps (1947), and Henri Verneuil's Le Colonel Chabert (1943) and Les Grandes Familles (1958). His final film role was in Les Grandes Familles.
Beyond acting, Debucourt also directed a few films, including Les Deux Gosses (1936) and Deuxième Bureau contre Kommandantur (1939). He was also a respected voice actor and narrator, lending his distinctive voice to numerous documentaries and radio broadcasts, further solidifying his reputation for clarity and gravitas.
Jean Debucourt passed away in Paris in 1958, leaving behind a legacy as a quintessential French actor, celebrated for his intellectual approach to performance and his lasting contributions to both theatre and cinema.