Operational assignments include tours with Marine Fighter Attack Squadrons 212, 235, 232 and 122 where he flew the F-4 Phantom II. In 1985 Lieutenant General Amos assumed command of Marine Air Base Squadron 24, later recommissioning it as Marine Wing Support Squadron 173. After transitioning to the F/A-18 Hornet in 1991, he assumed command of Marine Fighter Attack Squadron 312 and subsequently joined Carrier Air Wing Eight onboard USS Theodore Roosevelt (CVN-71). It was during this tour that VMFA-312 earned the Hanson Trophy as the Marine Corps' "Fighter Squadron of the Year.”

Lieutenant General Amos assumed command of Marine Aircraft Group 31 Beaufort, SC in May 1996. In August 2002, he assumed command of the Third Marine Aircraft Wing and deployed with 3d MAW to Operation Iraqi Freedom I and II during his time in command.Lieutenant General Amos' staff assignments include tours with Marine Aircraft Groups 15 and 31, the III Marine Amphibious Force, Training Squadron Seven, The Basic School, and with the MAGTF Staff Training Program. Promoted to Brigadier General in 1998 he was assigned to NATO as Deputy Commander, Naval Striking Forces, Southern Europe, and as the U.S. Deputy Commanding General, Fleet Marine Forces, Europe, Naples Italy. During this tour he commanded NATO's Kosovo Verification Coordination Center, and served as Chief of Staff, U.S. Joint Task Force Noble Anvil during Operation Allied Force. Transferred in 2000 to the Pentagon, he was assigned as Assistant Deputy Commandant for Aviation. Reassigned in December 2001, Lieutenant General Amos served as the Assistant Deputy Commandant for Plans, Policies and Operations Department (Code PL), Headquarters, Marine Corps. He assumed command of II Marine Expeditionary Force in July 2004.

Lieutenant General Amos is a graduate of the Armed Forces Staff College, Norfolk, VA and the Air War College, Maxwell AFB, AL. His personal decorations include the Distinguished Service Medal, Defense Superior Service Medal, the Legion of Merit (two awards), the Bronze Star, Meritorious Service Medal, Joint Service Commendation Medal, the Navy and Marine Corps Achievement Medal, as well as numerous campaign and service awards.