During the First Silesian War, Gessler distinguished himself at Mollwitz and at Chotusitz, in which he led the cavalry of Wilhelm Dietrich von Buddenbrock's left wing. After the battle, Gessler was promoted to "Generalleutnant" and awarded the Order of the Black Eagle. In the Battle of Hohenfriedberg, his ride with the Bayreuth Dragoon Regiment, in which 67 standards were captured, became one of the most storied attacks of the Prussian cavalry. In the Battle of Kesselsdorf on 15 December 1745, Gessler led the cavalry of the right wing.