Chase attended a machine gun course at Fort Sill, after which he was posted to the 11th Machine Gun Battalion, part of the 4th Division, in April 1918. He served on the Western Front with the 4th Division, participating in the Battle of Saint-Mihiel, but came down with jaundice and missed all but the last days of the Meuse-Argonne Offensive. He participated in the Occupation of the Rhineland before the 4th Division returned to the United States in July 1919.