He was the fourth son of Charles-Armand de Gontaut, duc Biron, and Marie Antoinette, Duchess of Lauzun. He joined the army as an adolescent. He fought in Italy (attack on the Milan castle, Tortona and the Battle of San Pietro).
He was the fourth child of Charles-Armand de Gontaut, duc Biron, and Marie Antoinette, Duchess of Lauzun. As a teenager, he joined the army and went on to fight in Italy, including the siege of Milan's castle, Tortona, and the Battle of San Pietro.