Schaal was born on 7 February 1889 in Freiburg im Breisgau, Baden. In April 1939, as part of the lead-up to the invasion of Poland, Schaal was tapped to lead the new 10th Panzer Division. He continued to command that unit through the invasions of Poland, France, and the USSR. On 16 March 1942, as the 10th Panzer Division returned to France from its bloody tour of the Eastern Front, Schaal was given the command of LVI Panzer Corps, which was also stationed in the Soviet Union. He served in that capacity until 1 August 1943, when he became Wehrmacht commander in the military district of Bohemia and Moravia.