In the War of the First Coalition, Knesebeck participated in the disastrous and personally disappointing Battle of Valmy and the subsequent victories at Primasens, as well as the First and Second Battles of Kaiserslautern. Frustrated by the contemporary discourse on the war, Knesebeck published a book under the pseudonym of a Swiss observer, examining the campaign in detail and errors in its public perception. Based on his experiences during the conflict he advocated for defense in depth, with strong logistics and supply lines, and combined with well-established fortresses. By 1794 Knesebeck's abilities had been noticed by the Duke of Brunswick, the commander of the Coalition's combined forces, and he was ordered to his staff, where he was promoted several times (1797 "Premierlieutenant", 1799 Captain, 1802 Major).