Hohenlohe-Kirchberg began his military career in 1756, when he joined the Habsburg regiment, the 29th Infantry Regiment "Braunschweig-Wolfenbüttel" as a young man. He served as a captain of grenadiers in the Seven Years' War. He was twice wounded, first at the famous Battle of Leuthen, and later at the Battle of Landshut, during the storming of Prussian redoubts. In 1758, he was promoted to major, in 1761, to lieutenant colonel, and in 1764, to colonel.