In 1921, he was elected a Senator for the Department of Corrèze; a position that was held by his father, Philippe-Michel Labrousse [fr], from 1894 to 1910.
Known for his oratorical skills, he was aligned with the Democratic Left [fr], and was involved with most of that period's controversial issues; notably the Locarno Treaties and the Kellogg-Briand Pact.
At Vichy, in 1940, he helped to rally a group of veteran Senators, in their vain attempts to oppose the constitutional changes being made.
Following the invasion of the zone libre by German troops, he became a special target for the Gestapo, forcing him, at the age of sixty-five, to join the Maquis.
That same year, as an amateur artist, he was elected to the Académie des Beaux-Arts; taking Seat #5 in the "Unattached" section.