He served in the French invasion of Russia (1812) and the next year became a prisoner of war after the Battle of Kulm.

Promoted to lieutenant general, Vaillant was put in charge of the building of the Parisian fortifications in 1845 under the command of Dode de la Brunerie.

In 1849, Vaillant was given command of the engineers in the French expeditionary corps to Rome.

In 1860, Vaillant became minister responsible for the Imperial House and in 1864, he was made Grand Chancellor of the Legion d'Honneur.

After the fall of the Second French Empire in September 1870, Vaillant was banished from France but was allowed back, returning in 1871.