He joined the British Army in 1743 as a cornet in the 6th (Inniskilling) Dragoons, was promoted captain in 1745, major in 1755, and lieutenant-colonel in 1763. He commanded the Inniskillings at the Battle of Minden in 1759. He sold out of the Army in 1768 and became MP for Kincardineshire. He bought the barony of Congalton in the parish of Dirleton, Haddington (now East Lothian).