Renton was commissioned into the Rifle Brigade in 1916 and served in World War I. He was appointed Deputy Assistant Adjutant General for the Iraq Levies in 1922. He also served in World War II as Commander of 2nd Bn the Rifle Brigade from 1940 (leading it and losing an arm at the Battle of Sidi Saleh in 1941) and as Commander of the Support Group of 7th Motor Brigade from 1942 (leading it at the Battle of Gazala). He was appointed General Officer Commanding 7th Armoured Division later that year. He went on to serve at the Senior Officers' School from 1943 before becoming Head of the British Military Mission and Inspector General of the Iraqi Army in 1944 and retiring in 1948.