Sarraut was born into an important Radical family that owned the newspaper Dépêche de Toulouse. Educated at the lycée of Carcassonne and the law faculty of Toulouse, he became a lawyer. As a member of the Chamber of Deputies (1902–24), Sarraut served as undersecretary of state (1906–09), undersecretary of war (1909–10), and minister of education (1914–15), and twice as governor-general of Indochina (1911–14, 1916–19). As governor-general he applied liberal policies, increasing the proportion of native Indochinese in the civil service, recognizing the use of the local languages and local law, and continuing the public-works policy of his predecessor, Paul Doumer. As minister for the colonies (1920–24, 1932–33), Sarraut sought to coordinate French colonial policy and promote development for overseas possessions, publishing La Mise en valeur des colonies françaises (1923; “The Improvement of French Colonies”) and Grandeur et servitude coloniales (1931; “Colonial Grandeur and Slavery”).

A senator from 1926 to 1940, Sarraut was minister of the interior (1926–28, 1934, 1937–40) and for the navy (1930–31) and twice premier (1933, 1936). Appointed premier in January 1936, he was angered by the German remilitarization of the Rhine but did not act. He resigned as premier in June.

Politically inactive during World War II, Sarraut became editor of Dépêche de Toulouse in 1943 after his brother Maurice had been murdered by a pro-Nazi gang. He was arrested by the German Gestapo in 1944 and released by the Allies in 1945. Unable to gain a seat in parliament, he became a member of the advisory assembly of the French Union in 1947, serving as its president from 1949 to 1958.