He served in the War of the Austrian Succession where he took part in the Battle of Lauffeld and the capture of Bergen op Zoom.

Upon his return to France in 1769 he was made colonel of the Légion de Lorraine en 1770.

Promoted maréchal de camp in 1780, Viomesnil served under Rochambeau in America during the Yorktown campaign.

After the outbreak of the French Revolution in 1791 Viomesnil decided to emigrate and join the army of Condé.

Originally designated to command the Russian forces sent to Italy he was replaced by Alexander Suvorov and sent instead to Jersey and Guernsey in anticipation of a joined invasion of France.