Born in Le Mée-sur-Seine into modest circumstances, Chapu moved to Paris with his family and in 1847 entered the Petit École with the intention of studying drawing and becoming an interior decorator.
In 1850 he began working and studying with a well-known sculptor James Pradier.
Following Pradier's death in 1852 Chapu began studying with another sculptor, Francisque Duret.
After coming in second in 1851, he won the Prix de Rome in 1855, then spent five years in Italy.
His statues Mercury of 1861 and Jeanne d'Arc of 1870 (in which she was represented as a peasant girl) were his first big successes, and led to many commissions thereafter.