 Butler was born on 23 October 1900 to George Butler and Harriet Clarke, at the family home of Maiden Hall outside the village of Bennettsbridge in County Kilkenny.Butler graduated in 1922 from St John's College, Oxford, where he studied classics.After being recruited by Sir Horace Plunkett to work for the Irish County Libraries from graduation until 1926, Butler later travelled extensively in Croatia, Serbia, Bosnia, Macedonia and Montenegro before working with the Quakers in Vienna expediting the escape of Jews after the Anschluss.