 He was the third but only surviving son of Thomas Butler of Garryricken and his wife Margaret Magennis.His father belonged to a cadet branch of the Butler Dynasty, being the grandson and heir of Richard Butler of Kilcash, who was the younger brother of James Butler, 1st Duke of Ormond.John's mother was the eldest daughter of William Burke, 7th Earl of Clanricarde and widow of Bryan Magennis, 5th Viscount of Iveagh.