He was elected as MP for Morpeth in 1689. He was appointed Governor of Carlisle from 1693 to 1728 and Lord-Lieutenant of Cumberland and of Westmorland from 1694-1714. William III made him a Gentleman of the Bedchamber between 1700 and 1702, First Lord of the Treasury from 1701 to 1702 and Privy Counsellor in 1701. He acted as Earl Marshal between 1701 and 1706 because his cousin, the Duke of Norfolk, was a minor. On Queen Anne's death on 1 August 1714 he was appointed Lord Justice of the Realm until the arrival of King George I on 18 September 1714. The new king reappointed him as First Lord of the Treasury from 23 May 1715 to 10 October 1715 and made him Constable of the Tower of London between 1715 and 1722.All of these offices came with large salaries, large opportunities to charge for favors, or both, and a career like this could make a man very wealthy indeed.