He joined the Army and became a captain (1755) and then major (1762) in the 58th Foot. He transferred to the 1st Foot Guards and was a captain, lieutenant-colonel (1774) and brigadier-general (in America) (1779). He was made colonel of the soon to be disbanded 80th Regiment of Foot (Royal Edinburgh Volunteers) in 1783 and elevated to major-general in 1787. In 1790 he was awarded the colonelcy of the 64th Foot, promoted lieutenant-general in 1797 and made full general in 1802. He had been with General Wolfe at Quebec in 1759 and in the West Indies in 1762.