Although born into a family of republican sympathies, Bainville came under the influence of the royalist propagandists Maurice Barrès and Charles Maurras and early embraced the cause of the restoration of the monarchy. After being associated with the royalist papers Action Française and Gazette de France, he published his first book, La République de Bismarck, ou Origines allemandes de la Troisième République (1905; “The Republic of Bismarck: German Origins of the Third Republic”), in which he emphasized the German chancellor Otto von Bismarck's support of French Republicanism.

During World War I Bainville wrote several works on Russia, Italy, and Germany; notable is his Histoire de deux peuples (1915; “History of Two Nations”), an anti-German work dealing with the recurrent German invasions of France. In 1920 he published Les Conséquences politiques de la paix (1920; “The Political Consequences of the Peace”), in which he attacked the Treaty of Versailles and predicted the danger of a unified Germany. His Histoire de France (1924) was later republished with other studies under the title Heur et malheur des français (“The Fortunes and Misfortunes of the French”). His Napoléon (1931) is an excellent psychological study. In his later years Bainville, concerned with the rising German threat, wrote Les Dictateurs (1935) and La Troisième République 1870–1935 (1935; The Third Republic), in which he predicted what he saw as two inevitable events: a German attack on France and a national revolution. He also published works on German and English history and literary essays. Bainville was elected to the Académie Française in 1935.