After his promotion to Generalmajor during World War II on 1 August 1940, Friessner was assigned to the Eastern Front on 1 May 1942 and placed in command of the 102nd Infantry Division. Shortly after his promotion to Generalleutnant on 1 October 1942, Friessner served as commander of the XXIII Corps from 19 January to 11 December 1943. On 1 April 1943, he was promoted General der Infanterie (General of the Infantry).