Wedemeyer was born in Omaha, Nebraska on 9 July 1897. He studied at the United States Military Academy in West Point and graduated in 1919. After the start of World War II, he was made a temporary Lieutenant Colonel in 1941. Between 1941 and 1943, he served as a staff officer in the war-plans division of the U.S. War Department. He was the chief author of the 1941 Victory Program which advocated the defeat of the German armies in Europe. When the U.S. entered the war this plan was adopted and expanded. He helped plan the invasion of Normandy.