Keith-Jones was educated at Clifton College.[1] He was commissioned into the Royal Artillery on 1 February 1934.[2] He saw action in the Italian campaign during the Second World War, for which he was awarded the Military Cross.[3][4]
After the war he became a GSO2 instructor at the Staff College, Camberley, from September 1949 until December 1951,[4] Commander, Royal Artillery (CRA) for 17th Gurkha Division in July 1957 and General Officer Commanding 50th (Northumbrian) Division/District of the Territorial Army in March 1964 before retiring in July 1966.[5][4]
Keith-Jones wrote the foreword to A Short History of the 50th Northumbrian Division by Major A.H.R. Baker and Major B. Rust TD, published in 1966, as General Officer Commanding 50th Northumbrian Division, from Kirkleavington Hall, Yarm, Yorkshire.[6]
During the 1950s, Keith-Jones was a military assistant to Field Marshal Montgomery as part of Montgomery's NATO Deputy Supreme Allied Commander Europe staff. Keith-Jones became the second commandant of the Joint Warfare Establishment in 1966.[1]
He was appointed a Member of the Order of the British Empire in the 1947 Birthday Honours[7] and a Companion of the Order of the Bath in the 1968 New Year Honours.[8][4]