French politician and wealthy businessman who served brief and undistinguished terms as a premier and as the fifth president of the Third Republic.

The son of a former minister of the interior, he served as a captain during the Franco-German War (1870–71). In 1876 he was elected to the Chamber of Deputies as a Left Republican from Aube département, serving as the chamber's vice president (1890–92) and president (1893). On Dec. 4, 1893, he formed his own cabinet, which fell within six months because of his inability to cope with anarchist terrorism and the vexing church-state issue.

Casimir-Périer returned to the presidency of the chamber (June 1894) and in the wake of the assassination of Sadi Carnot was elected (June 27, 1894) president of the Third Republic. Unable to control his premier, Charles-Alexandre Dupuy, and faced with the mounting fury of the Dreyfus Affair, he quickly became a target for the political left. His most vigorous assailant, the journalist Gérault-Richard, was convicted of slander, but then the Socialist leader Jean Jaurès picked up the cudgel. Gérault-Richard's release by the Chamber of Deputies proved so embarrassing that, after only six months in office, Casimir-Périer resigned, abandoning politics to become chairman of the vast Anzin mining enterprise, of which he was one of the largest shareholders.