Then, he joined the Württemberg service. First, he became captain and then rose in rapid succession, so in 1807, he was colonel of the 1st Battalion of the Kronprinz Regiment. In 1808, he was a major general. By 1812, he was a lieutenant general. He commanded the Foot Guards in 1814. On 6 November 1813, he was promoted to field-marshal. In the Napoleonic Wars, he was on the side of Napoleon, at the Battle of Wartenburg, Battle of Bautzen, where he was severely wounded, and Battle of Dennewitz.