Boyle became Commander-in-Chief, Ireland in 1720 and retained that command for the rest of his life. In June 1721 Richard Waring sold the colonelcy of the King's Regiment of Carabineers to Boyle for £7,500. Boyle also became a member of the Privy Council of Ireland in 1721 and one of the Lord Justices in Ireland in 1722. Awarded the Freedom of the City of Cork in 1722, he was ousted from his seat in Parliament as a result of a petition but regained his seat again in a by-election later that year.