Fleury began his stage apprenticeship at Nancy, Fr., where his father was an actor at the court of Stanisław I, duke of Lorraine and Bar. After encouragement from Voltaire, he acted at the Comédie-Française in 1774 but returned to the provinces for further study, performing chiefly at Lyon.

When Fleury returned to Paris in 1778 he was made a full member of the Comédie-Française, for which he served as doyen, or leader, until his retirement in 1818. During the French Revolution he and many of his fellow players were arrested (1793) for presenting a politically controversial play, L'Ami des Lois (“The Friend of Laws”). When liberated, Fleury appeared at various theatres until, in 1799, he rejoined the reconstituted Comédie-Française. A master of comedy, he was especially noted for his brilliant characterization of Alceste in Molière's Misanthrope.