Though committed to an acting career in his teens, Boyer nevertheless acceded to his mother's request that he graduate from the Sorbonne (with a degree in philosophy) before studying acting at the Conservatoire de Paris. At the age of 21 Boyer stepped into his first leading role on 12 hours notice when the star of the play fell ill. In the 1920s he was not only the most popular romantic leading man on the Paris stage but was steadily employed in silent films.

Boyer went to Hollywood at the beginning of the sound era, and Private Worlds (1935), his third film there, made an international star of the handsome actor with the rich, accented voice. His long, distinguished career included the motion pictures Algiers (1938), All This and Heaven Too (1940), Gaslight (1944), Around the World in 80 Days (1956), How to Steal a Million (1966), and Stavisky (1974).