His elder brother, John, was the 10th Duke of Marlborough. His stepmother was the former Gladys Deacon, and his stepfather was Col. Jacques Balsan. Spencer-Churchill was educated at Eton College and Magdalen College, Oxford, before joining the Royal Army Service Corps in 1917 and gaining the rank of lieutenant. He fought in the First World War and was decorated with the French Legion of Honour. He married Elizabeth Cunningham on 15 November 1947 and had a son, Robert William Charles (born 1954).