His breakthrough role was in Jean-Luc Godard's Breathless (1960), which made him a major figure in the French New Wave. Later he acted in Jean-Pierre Melville's philosophical movie Leon Morin, Priest (1960), then in the Film Noir crime film The Fingerman (1963). With That Man From Rio (1965) he switched to commercial, mainstream productions, mainly comedies and action films. Until the mid-1980s, Belmondo's typical characters have been either dashing adventurers or more cynical heroes. He was one of France's biggest box-office stars until the mid-1980s. As he grew older, Belmondo preferred concentrating on his stage work, where he encountered success. He suffered a stroke in 2001 and has since been absent from the stage and the screen.
In 1953, Belmondo married Élodie Constantin, with whom he had three children: Patricia (1958), Florence (1960) and Paul (1963). Paul became a Formula One driver; his eldest daughter Patricia was killed in a fire in 1994.
In 1966, due to a well-publicized affair between Belmondo and actress Ursula Andress, Belmondo and his wife divorced.
In 1989, Belmondo met Nathalie Tardivel who was 24 years old at the time. Belmondo married her in 2002. On 13 August 2003, at the age of 70, his fourth child Stella was born.
In 2008, Belmondo and Tardivel divorced.
The main character Nick Twisp in the Youth In Revolt series by C.D. Payne is said to resemble Belmondo numerous times.