Pérusse des Cars served in the French Navy before he joined the Army and was appointed Maître de camp (equivalent to Colonel) of the Dragoons-Artois regiment in 1774. After the death of his second brother during the Battle of the Saintes in 1782, he took the title Baron des Cars. In 1783, he became first Maître d'hôtel du Roi of the King. In January 1784, he was made a Brigadier of cavalry followed by Lt.-Gen. on 9 March 1788. He served as député aux États-généraux in 1789, and left the country with the French princes in 1790 during the French Revolution. In 1791, he was sent on a diplomatic mission to King Gustav III of Sweden, followed by further missions, including in Berlin.