Educated at Eton College and the Royal Military Academy Sandhurst, Langley was commissioned into the Life Guards in 1949. He was posted to Egypt and then to Libya. He then served with HQ Far East Land Forces during the Indonesia–Malaysia confrontation in the early 1960s. He later became Commanding Officer of the Household Cavalry Regiment and Silver Stick to The Queen. In 1976 he was appointed commander of 4th Guards Armoured Brigade and in 1978 he became a brigadier on the General Staff at UK Land Forces.