Major General Ronald James Fairfield, Jr. was commissioned an Armor Officer upon graduation from Tank Destroyer Officer Candidate School at Camp Hood, Texas, in February 1943. | His subsequent duty assignments include:  S-2, Alabama Military District, Alabama; Company Commander, 89th Tank Battalion, 25th Infantry Division, Korea; S-3, 89th Tank Battalion, 25th Infantry Division, Korea; Instructor, Armor Committee, Tactics Department, Infantry School, Fort Benning, Georgia; Instructor, Seventh Army Tank Training Center, Vilseck, Germany; Executive Officer, 3d Reconnaissance Squadron, 12th Cavalry, 3d Armor Division, Germany; Commanding Officer, 3d Reconnaissance Squadron, 12th Cavalry, 3d Armor Division, Germany; Action Officer, Office of the Deputy Chief of Staff for Military Operations, Department of the Army; Secretary for Joint Actions, Office of the Deputy Chief of Staff for Military Operations, Department of the Army; Commanding Officer, 1st Battalion, 69th Armor, 25th Infantry Division; Deputy Chief of Staff, I Corps Field Force; Commander, Support Command, 3d Infantry Division, Wuerzburg, Germany, Special Assistant to the Chief of Staff, Supreme Headquarters Allied Powers, Europe; Assistant Executive and Senior Aide, Supreme Allied Command, Europe; Assistant Division Commander, 7th Infantry Division, Korea; Chief of Staff, I Corps; Commanding General, U.S. Army Concepts and Force Design Group of U.S. Combat Developments Command, Vietnam; Deputy Commanding General, 3d Regional Assistance Command, Vietnam; Special Assistant to the Commander, US Forces, Vietnam; Deputy to the Inspector General, Department of the Army; Acting Inspector General, U.S. Army; Commanding General Military District of Washington; Honorary Commander, 69th Armor Regiment.