 He was created Baron Bruce of Whorlton, in the Peerage of England, on 29 July 1641.In 1643, he was appointed "Keeper of the King's Park" at Byfleet, a role he held until 1647.Although Bruce's sister Christian Cavendish, Countess of Devonshire was a notable Royalist, Bruce himself took the side of the Parliamentarians, serving on several county committees from 1644 to Pride's Purge.