Ladmirault was born on 17 February 1808 at Montmorillon[1] to an old family belonging to the Poitou minor aristocracy.
Ladmirault entered the prestigious Saint-Cyr Military School in 1826 (in the same class as the future Marshal of France François Certain Canrobert).
He participated in the Italian war of 1859, commanding the 2nd division of I Corps under Marshal Achille Baraguey d'Hilliers, and taking part in the Battle of Solferino, during which he was wounded twice.
During the Franco-Prussian War he was placed in command of the IV Corps of the Army of the Rhine, taking part in the battles of Mars-la-Tour and Saint-Privat; during the latter he repulsed the German attack at Amanvillers.
After the suppression of the Commune, he was named military governor of Paris, a post he held until 1878.