Callan, County Kilkenny
Thomas was probably born at Garryricken, near Callan, County Kilkenny, as the eldest son of Walter Butler and his wife Mary Plunkett. His father, known as Walter Butler of Garryricken (died 1700), belonged to a cadet branch of the Butler Dynasty, being the son of Richard Butler of Kilcash (died 1701), who was a younger brother of the 1st Duke of Ormond. Thomas's father had built Garryricken House around 1660. The Butler dynasty is an Old English family that descends from Theobald Walter, who had been appointed Chief Butler of Ireland by King Henry II in 1177. Thomas's mother was the only daughter of Christopher Plunkett, 2nd Earl of Fingall.