Lord of Mann from 1736 until his death in 1764, and the last proprietor before the sale of the Island.

He succeeded the tenth Earl of Derby in the Lordship and took possession in 1736. An account of that first visit, printed by the Manx Society more than a century later and not published before, describes his holding a Tynwald Court at St John's on midsummer day. It is the earliest detailed report of the Manx legislature in Tynwald assembled, newspapers being then unpublished on the Island. Bishop Wilson preached before that court.

His assent to Manx legislation was given at a distance. The Act of 1738 was confirmed under his hand at Dunkeld on 5 June, signed Atholl and Strange, with an order that it be proclaimed on the Tynwald Hill according to ancient form and custom.

Basil Cochrane reported to him as Governor through the later 1750s, and petitions from the Island were addressed to him as Duke of Athole, Baron Strange, Lord of Man and the Isles.

He died in 1764. Charlotte, his only surviving child, succeeded on 8 January that year, and her husband and first cousin John Murray became third Duke as nephew and heir male.