Born Jean-Alexis Moncorgé in Paris, France, he grew up in the village of Mériel in the Seine-et-Oise département, about 22 mi (35 km) north of Paris. The son of cabaret entertainers, he worked as a laborer, but at age 19 entered show business with a bit part in a Folies Bergères production. He continued performing in a variety of minor roles before going into the military.

After completing his military service, Gabin returned to the entertainment business, working under the stage name of Jean Gabin at whatever was offered in the Parisian music halls and operettas. 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.

Two years later, he easily made the transition to talkies in a 1930 Pathé Frères production titled Chacun sa Chance. Playing secondary roles, Gabin made more than a dozen films over the next four years, including films directed by Maurice and Jacques Tourneur. However, he only gained real recognition for his performance in Maria Chapdelaine, a 1934 production directed by Julien Duvivier. Cast as a romantic hero in a 1936 war drama titled La Bandera, this second Duvivier-directed film established Gabin as a major star. The following year, he teamed up with Duvivier again, this time in the highly successful Pepe le Moko that became one of the top Grossing Films of 1937 worldwide; its popularity brought Gabin international recognition. That same year, he starred in the Jean Renoir masterpiece La Grande Illusion, an anti-war film that was a huge box office success and given universal critical acclaim, even running at a New York City theater for an unprecedented six months.

Flooded with offers from Hollywood, for a time Gabin turned them all down until the outbreak of World War II. Following the German occupation of France, he joined Jean Renoir and Julien Duvivier in the United States. Divorced from his second wife in 1939, during his time in Hollywood, Gabin began a torrid romance with actress Marlene Dietrich. However, his films in America proved less than successful.

A difficult personality with a very large ego, he did serious damage to his Hollywood career while working for RKO Pictures. Scheduled to star in an RKO film, at the last minute he demanded Dietrich be given the co-starring role. The studio refused. After Gabin remained steadfast in his demand, he was fired, and the film project was shelved.

Undaunted, Jean Gabin joined General Charles de Gaulle's Free French Forces and earned the Médaille Militaire and a Croix de Guerre for his wartime valor fighting with the Allies in North Africa. Following D-Day, Gabin was part of the military contingent that entered a liberated Paris. Captured on film by the media is a scene where an anxious Marlene Dietrich is waiting in the crowd when she spots Gabin onboard a battle tank and rushes to him.

In 1946, Gabin was hired by Marcel Carné to star in the film, Les Portes de la Nuit, but his egotistical conduct got him fired again. He then 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 there too, the production was another financial disaster. Nevertheless, he was cast in the lead role of the 1949 René Clément film Au-Dela Des Grilles that 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 box office failures.

Gabin's career seemed headed for oblivion. However, he made a comeback in the 1954 film, Touchez pas au grisbi. Directed by Jacques Becker, his performance earned him critical acclaim, and the film was very profitable international success. Over the next twenty years, Gabin made close to 50 more films, including many for Gafer Films, his production partnership with fellow actor Fernandel.

Gabin died of a heart attack in the Parisian suburb of Neuilly-sur-Seine. His body was cremated and with full military honors, his ashes were dispersed into the sea from a military ship.

Considered one of the great stars of French cinema, he was made a member of the Legion of Honor. The Musée Jean Gabin in his native town, Mériel, contains his story and features his war and film memorabilia.