A lieutenant-colonel of the Royal Scots Regiment, James Murray first entered politics in 1715 as MP for Perthshire. When Murray?s elder brother, William, became involved in the 1715 Jacobite rebellion he was dishonoured and could no longer inherit his father?s title or property. James himself was a supporter of the Hanoverian kings, and on the death of his father he inherited the family titles and estates instead. He later resigned his military post and replaced the Earl of Islay as Keeper of the Privy Seal of Scotland. In 1746 he accompanied the Duke of Cumberland north to crush the Jacobite army, led by his other brother, Lord George Murray, who at one point besieged the family?s ancestral home of Blair Castle when it was occupied by Hanoverian troops.