Robin Grist was born and brought up in Gloucestershire. Commissioned into the Gloucestershire Regiment in 1960, he later flew with the Army Air Corps. He took command of 1st Glosters in 1980. He became Director of the Army Air Corps as a Major General. He was Colonel of the Gloucestershire Regiment (1991-1994) and Colonel of the Royal Regiment of Gloucestershire, Berkshire and Wiltshire until 2004.
After retiring he was closely involved in the economic development of Gloucestershire, and was Chairman of the Gloucestershire Community Foundation and a Deputy Lieutenant (1994-2002).