He served in the American Revolutionary War as an aide-de-camp to his father, spending the winter of 1781–1782 in quarters at Williamsburg, Virginia.

Rochambeau was later assigned to the French Revolutionary Army in the Italian Peninsula, and was appointed to the military command of the Ligurian Republic.

Historians of the Haitian Revolution credit his brutal tactics for uniting black and gens de couleur soldiers against the French.

He used a rudimentary method of filling ships' cargo holds with sulfur dioxide to suffocate black prisoners of war.

[3][4] At the surrender of Cap Français, Rochambeau was captured aboard the frigate Surveillante by a British squadron under the command of Captain John Loring and returned to England as a prisoner on parole, where he remained interned for almost nine years.