Wilhelm René de l'Homme de Courbière was born on 25 February 1733 into a Franco-Dutch family, paternally expatriates from the Dauphiné province, in Maastricht in the Dutch Republic. Following his father, Alexis Baron de l’Homme de Courbière, young Courbière joined the Dutch States Army in 1746. He served with the Regiment d’Aylva in the War of the Austrian Succession, participating in the defense of Bergen op Zoom. He left Dutch service in 1753 and entered the Prussian Army as a company commander in 1757. Then he served in the Third Silesian and Pomeranian wars. Gaining the attention of King Frederick the Great, after the Siege of Schweidnitz (1758) he was given the rank of Major and command of a free battalion. After the Siege of Dresden he received the Pour le Mérite. He also fought at Liegnitz and Torgau.