He participated in the American Revolution, and before attaining the rank of field marshal, he commanded various regiments, including the 3rd Regiment of Foot, the 1st (The King's) Dragoon Guards, and the 7th (The Queen's Own) Regiment of Dragoons. He became field marshal on 12 October 1793, and was previously made a Privy Councillor and a Knight of the Bath. He served in the House of Commons as Member of Parliament (MP) for Lostwithiel from 1761 to 1766 and for Stamford from 1768 until his death.