After completing his military Service in the Fusiliers marins, he returned to the entertainment Business, working under the stage name of Jean Gabin at whatever was offered in the Parisian music halls and operettas, imitating the singing style of Maurice Chevalier, which was the rage at the time. He was part of a troupe that toured South America, and upon returning to France found work at the Moulin Rouge. His performances started getting noticed, and better stage roles came along that led to parts in two silent films in 1928.

In the late 1930s Gabin was flooded with offers from Hollywood; for a time he turned them all down, until the outbreak of World War II. After the German occupation of France in 1940, he joined Jean Renoir and Julien Duvivier in the United States. During his time in Hollywood, Gabin began a romance with Actress Marlene Dietrich which lasted until 1948. However, his films in America – Moontide (1942) and The Impostor (1944), the later reuniting him with Duvivier – were not successful.

He was hired by Marcel Carné in 1946 to star in the film, Les Portes de la Nuit, but his conduct got him fired again. He found a French Producer and Director willing to cast him and Marlene Dietrich together, but their film Martin Roumagnac was not a success and their personal relationship soon ended. Following another box office failure in 1947, Gabin returned to the stage, but the production was a financial disaster. Nevertheless, he was cast in the lead role of the 1949 René Clément film Au-Delà Des Grilles, which won the Academy Award for Best Foreign Language Film. Despite this recognition, the film did not do well at the French box office, and the next five years brought little more than repeated failures.

His career seemed headed for oblivion. However, in the 1954 film Touchez pas au grisbi (Don't Touch the Loot), directed by Jacques Becker, Gabin's performance earned him critical acclaim. The film was very profitable internationally. He then worked once again with Jean Renoir in French Cancan, with María Félix and Françoise Arnoul. Gabin played Georges Simenon's detective Jules Maigret for three films in 1958, 1959 and 1963. Over the next twenty years he made almost 50 more films, most of them very successful commercially and critically, including many for Gafer Films, his production partnership with fellow actor Fernandel. His co-stars included leading figures of post-war cinema such as Brigitte Bardot (En cas de malheur), Alain Delon (Le Clan des Siciliens, Mélodie en sous-sol and Deux hommes dans la ville), Jean-Paul Belmondo (Un singe en hiver) and Louis de Funès (Le Tatoué).

Gabin died of leukaemia at the American Hospital of Paris, in the Parisian suburb of Neuilly-sur-Seine. His body was cremated, and—with full military honours—his ashes were scattered at sea from a military ship.