Born the eleventh child in a poor family from Montpellier, Lepic joined a dragoon regiment at age 16 and benefitted from the outburst of the French Revolution, which facilitated his promotion to squadron commander (March 1793).

Lepic remained in Italy until the end of 1805, when he was named colonel major of the Grenadiers à Cheval de la Garde Impériale regiment of the newly created Imperial Guard, which he would command for the rest of his military career.

The ensuing heroic charge at the head of his horse grenadiers, where he was seriously wounded, brought him the rank of général de brigade.

During the campaign, his most important action was his regiment's charge against Platov's cossacks on November 7, which repulsed the Russian attack on the Emperor's headquarters.

Lepic was promoted to général de division in February 1813, and he took part in the Saxon campaign of the War of the Sixth Coalition, where he would fight his last battles.