Born in Paris, Léaud made his major debut as an actor at the age of 14 as Antoine Doinel, a semi-autobiographical character based on the life events of French film director François Truffaut, in "The 400 Blows". To cast the two adolescents, Truffaut published an announcement in "France-Soir" and auditioned several hundred children in September and October 1958. Jean Domarchi, a critic at "Cahiers du cinéma", had earlier recommended the son of an assistant scriptwriter, Pierre Léaud, and the actress Jacqueline Pierreux.