 Schlemm joined the Prussian Army in 1913.During the inter-war years, Schlemm served in a variety of staff, training and regimental posts until, in October 1937, he was attached to the Reich Air Ministry.In February 1938, he transferred from the Army to the Luftwaffe and was appointed to the Luftwaffe General Staff and in June 1938, he became Chief of Staff of Air Defense Zone West.