In April 1943, he was placed in command of a newly formed III SS Panzer Corps. The unit participated in anti-partisan actions in Yugoslavia. In November/December 1943 his corps was transferred to the Eastern Front and positioned in the northern sector at Leningrad under Army Group North. Steiner's Panzer Corps played a leading role during the Battle of Narva and the Battle of Tannenberg Line. His unit then withdrew with the rest of Army Group North to the Courland Peninsula.