When World War I broke out, Glücks returned to Germany under a false identity on a Norwegian ship in January 1915 and joined the army again. During the war, he eventually became the commander of an artillery unit and was awarded the Iron Cross I and II.[1] Glücks fought at the Battle of Verdun and the Battle of the Somme.[2] After the war, he became a liaison officer between the German forces and the Military Inter-Allied Commission of Control, the allied body for controlling the restrictions placed upon Germany in the Treaty of Versailles regarding re-armament and strength of their armed forces. Until 1924, he stayed in that position, before joining the staff of the 6th Prussian Division.