 He graduated on June 7, 1944, with Bachelor of Science degree in electrical engineering and was commissioned second lieutenant in the Marine Corps on the same date.Upon his graduation, Mize completed the Reserve Officers Course at Marine Corps Schools, Quantico in January 1945 and was ordered to Camp Lejeune, North Carolina, where he joined 55th Replacement Draft as platoon leader.He was attached as Rifle platoon leader to the Company F, 2nd Battalion, 29th Marines under Colonel Victor Bleasdale and sailed with 6th Marine Division for Okinawa in March 1945.