His elder brother, William, died in infancy in 1694, and Archibald was thereafter styled Earl of Angus.
During the Jacobite rising of 1715, Douglas took the Hanoverian side, and led the volunteer horse at the Battle of Sheriffmuir.
In maturity, Douglas grew eccentric, and perhaps insane, slew Captain John Kerr (the natural son of his uncle, Lord Mark Kerr) at Douglas Castle, while the latter was guesting with him there, and was forced to flee for some time to Holland.
He fell out with his sister, Lady Jane Douglas, when he discovered her secret marriage to Sir John Stewart, 3rd Baronet of Grantully, and treated her with great cruelty.
In 1755, Douglas Castle burned, and he hired Robert Adam to rebuild it, although the work was never finished, being halted by the Duke's death.