Educated at Kelly College in Tavistock and Mons Officer Cadet School, Elliot was commissioned into the South Wales Borderers in 1966. He saw service in Northern Ireland and was mentioned in despatches in 1975. He became Commanding Officer of 1st Bn Royal Regiment of Wales in 1987. He went on to be Commander of British Forces in Belize in 1990, Director of Army Recruiting at the Ministry of Defence in 1993 and British Military Advisor in South Africa in 1994. After that he became General Officer Commanding UK Support Command (Germany) in 1997 and then served as Defence Services Secretary and Director General, Reserve Forces and Cadets from 2001 to 2004.