Dawson enlisted in the Army in May, 1941 as a private, and rapidly was promoted to corporal. He applied for admission to Officer Candidate School, and his application was accepted and he entered OCS at Fort Benning, Georgia, in December, 1941. He graduated in March, 1942 and received his commission as a second lieutenant. He sought to be assigned to the First Division, the fabled Big Red One, since that assignment offered the most immediate prospect for combat duty. He initially was assigned to the 1st platoon, Company A, 1st Battalion, 16th Regiment. After Gen. Terry Allen assumed command of the 1st Division, Dawson was assigned to serve on his staff.