 John Hamilton, 1st Marquess of Abercorn, was his great-grandfather and James Hamilton, 1st Duke of Abercorn, his uncle.In 1904 he assumed by Royal licence the surname of Proby in lieu of his patronymic.He was educated at Eton College and matriculated on 15 January 1875 at Christ Church, Oxford, where he graduated with a Bachelor of Arts in 1879 and a Master of Arts in 1912.