 Hope-Wallace was born in London, the third and youngest child and only son of Charles Nugent Hope-Wallace, MBE, principal clerk of the Charity Commission for England and Wales, and his wife, Mabel Florence, daughter of Colonel Allan Chaplin, of the Madras Army.Charles Hope-Wallace was a descendant of John Hope, 4th Earl of Hopetoun and of George Nugent, 7th Earl of Westmeath, as well as of the Scottish Clan Bethune of Balfour.Philip attended Charterhouse School, after which, owing to a weak chest, he was sent to a sanatorium in Germany.