Louis Baraguay d'Hilliers was born in Paris. He was a minor noble and entered the French Army as a lieutenant in 1784. At the start of the French Revolutionary Wars, he decided to remain in France. By 1793, he had been promoted during the siege of Mainz to général de brigade and served as chief of staff to Adam Custine. When Custine was arrested, Baraguey d'Hilliers was arrested as well. Luckier than his chief who died under the guillotine, he was released after the overthrow and execution of Maximilien Robespierre.