He served with the Coldstream Guards during the Second World War, and after succeeding his uncle in the peerage in 1952, became a Lord-in-Waiting and Lord Lieutenant of Surrey.
Their children included James Leslie Hamilton (1938–2006), later the fourth Baron, and Archibald Gavin ("Archie"), born at Beckington in 1941,[4] later a Conservative politician and life peer.
[5] During the Second World War, Hamilton saw active service with his regiment's 5th Battalion, which formed part of the Guards Armoured Division, in the Battle of Normandy, and was injured there on 18 July 1944.
[9] In 1961, he was with Queen Elizabeth II at Kingston on Thames as Vice Lord Lieutenant for Surrey.
[13] Lady Hamilton's sister Celia was the grandmother of Jack Brooksbank, who married the Queen's granddaughter Princess Eugenie in 2018.