Einar A. Rogstad, from Becker County, Minnesota, joined the United States Marine Corps (USMC) in 1917 to fight in World War I. He served overseas from May 1918 to May 1919, fighting at St. Mihiel, Marbache, Champaigne, and in the Meus-Argonne Offensive. After the signing of the Treaty of Versailles, he remained in Europe during peacetime as part of the Army of Occupation.