Born in 1899 in Fresnay-sur-Sarthe, Brianchon initially studied briefly at the École des Beaux-Arts in Bordeaux, then from 1917 in Paris at the École des Arts Décoratifs, where he studied under Eugène Morand and befriended Leguelt and Desnoyer.
From 1922 Brianchon and Leguelt shared a studio, and in the same year Brianchon was appointed committee member of the Salon d’Automne. In 1924 he was awarded the Prix Blumenthal and a scholarship from the École des Arts Décoratifs which enabled him to travel through Spain, where he was strongly influenced by Velasquez. In 1925 he and Leguelt painted the scenery for the ballet La Naissance de la Lyre at the Paris Opéra. In 1927 his first solo exhibition was held at Galerie Le Portique.
In 1929 Brianchon visited Perigord for the first time; he would return for summers in his later years. In 1934 Brianchon participated in Artists of our Age exhibition at the Musée du Petit Palais and represented France with six paintings at the Venice Biennale, hung next to work by Manet. He married Marguerite Louppe, an artist, in the same year. Brianchon was appointed professor at the Ecole des Arts Décoratifs in 1936. He worked on murals for the Opéra in 1941, and in 1948 visited Carnac, where most of his seascapes were painted. The following year he was appointed professor at the École Nationale des Beaux-Arts. In 1951 he had a retrospective at the Louvre, as well as a solo exhibition at Wildenstein Gallery in London.
Brianchon’s reputation as one of the most respected painters of his generation led to the British Government requesting his attendance at Queen Elizabeth II’s coronation, to document the ceremony. Between 1956 and 1975 he had a series of solo exhibitions at Arthur Tooth & Sons in London, and at David Findlay Galleries in New York. In 1962 he also had a retrospective at the Musée des Beaux-Arts, in Neuchâtel in Switzerland, and in 1972 an exhibition at the Yoshii Gallery in Tokyo entitled Hommage à Brianchon. He has been seen by many as a successor in style and subject to the ‘Intimisme’ of Bonnard and Vuillard. He died in Paris in 1979.