Mattis enlisted in the Marine Corps Reserve in 1969. He was commissioned a second lieutenant through the Naval Reserve Officers' Training Corps on January 1, 1972. During his service years, Mattis was considered an "intellectual" among the upper ranks. Robert H. Scales, a retired United States Army major general, called him "one of the most urbane and polished men I have known." As a lieutenant, Mattis was assigned as a rifle and weapons platoon commander in the 3rd Marine Division. As a captain, he was assigned as the Naval Academy Preparatory School's Battalion Officer, commanded rifle and weapons companies in the 1st Marine Regiment, then served at Recruiting Station Portland, Oregon, as a major.