From 1941 to 1943, he served under Field Marshal Fedor von Bock, his wife's cousin, and later Field Marshal Günther von Kluge as chief operations officer of the German Army Group Centre in Operation Barbarossa, the invasion of the Soviet Union. Subsequently, in October and November 1943, he served in combat as the commanding officer of Grenadier Regiment 442, defending the western bank of the Dnieper River in Ukraine. From December 1943 until his death in 1944, he served as Chief of Staff of the 2nd Army, in areas which are now Belarus and eastern Poland.