Thomas Butler, as an Irish peer, should only have sat in the Irish parliament. However, as a personal friend of Henry VII of England, he was summoned to the English parliament in November 1488 as "Thomas Ormond de Rochford, chevaler". At this time, he was already 8th Earl of Carrick and 7th Earl of Ormond, having succeeded his childless older brothers James Butler, 5th Earl of Ormond and John Butler, 6th Earl of Ormond. On his death, the "barony" supposedly created in 1488 fell into abeyance. He was afterwards sworn of the Privy Council of England.

He was known as The Wool Earl, due to his enormous wealth. Besides being in the possession of major lands in the Irish counties of Kilkenny and Tipperary, he owned 72 manors in England, making him one of the richest subjects in the realm.

In 1509, he was appointed Lord Chamberlain to Catherine of Aragon. He held this post until 1512.3301