Rudolf Lehmann attended the 2nd class at the officers school in Bad Tölz starting in April 1935. Upon his graduation he was assigned as a Zugfürher with "Germania" until April 1939. During his tenure with "Germania", Lehmann became the commander of the Panzerspähzug (armored car platoon). He became Kompanie Chef of 14/Germania in April 1940 where he remained until transferring to the "Leibstandarte" in October 1940. Lehmann served as the Ordonnanzoffizier until August 1941 when he was hospitalized. After convalencing, he was given more training and then was assigned as Ia to LSSAH in early June 1942. Lehmann was considered as one of the best staff officers of the Waffen-SS, becoming Sepp Dietrich's primary advisors. After another stint in the hospital, Lehmann was recommended for the Knight's Cross by Theodor Wisch. His award of the Knight's cross stemmed from his leadership of a hastily assembled Kampfgruppe in the Zhitomir area during December 1943. In late 1944, Lehmann became the Chief of Staff for I.SS Panzer Korps and was under Sepp Dietrich. He remained at this position until March 1945, when he assumed command of "Das Reich" and led the Division through the difficult battles of Vienna and was awarded the Oakleaves for his leadership of DR. Wounded during the fighting in Austria, Lehmann spent the remainder of the war recovering from his injuries.