Pierre Billet is the son of an industrialist established in Cantin. He abandoned this activity to become a student of the painters Émile Breton and Jules Breton.
He began at the Salon of French Artists in 1868 where he presented genre scenes. He received a 3rd class medal in 1873 and a 2nd class medal in 1874.
He creates realistic scenes, in the style of Jules Breton, rural (Douaisis) or maritime (Boulogne, Yport). After 1900, his art moved towards post-impressionism.
Pierre Billet trains students in painting, including his daughter Aline Guérin-Billet, Georges Maroniez or Maurice Lévis
He rubbed shoulders with the family of Jules Breton, the Demon-Breton couple and certain painters from the Wissant School, including the couple Henri and Marie Duhem.