حملة البلقان
On 6 April 1941, Geißhardt shot down four Hawker Fury biplane fighter aircraft in the aerial battles against the Yugoslav Royal Air Force's 36th Fighter Group during the Balkans Campaign. During the German Invasion of Crete he claimed two Hawker Hurricanes. He was posted as an adjutant of the "Stab" to the I.(Jagd)/LG 2 at the end of April 1941.