 He was drafted and became a U.S. citizen as an inductee and joined the United States Army in April 1943 ("with two PhDs and one monocle") as an infantryman in the 84th Infantry Division (the "Railsplitter").Kraemer fought in the Battle of the Bulge and in the battles of the Ruhr and Rhineland, earning a Battlefield Commission and a Bronze Star in the liberation of his former homeland.In 1945 Kraemer was reunited with his wife and son and returned to Washington, DC, in 1947.