His paternal grandparents were Sir John Douglas, 3rd Baronet of Kelhead, MP for Dumfriesshire, and the former Christian Cunningham (a daughter of Sir William Cunningham, 2nd Baronet of Caprington).

Upon simultaneously inheriting Kinmount House, he commissioned a new house to be built by the English architect Sir Robert Smirke, which served as the seat for subsequent Marquesses of Queensberry and still stands.

He was made a Knight of the Thistle in the 1821 Coronation Honours[4] and created Baron Solway, of Kinmount, in the County of Dumfries, in 1833.

[5] From 1831 to 1837, he served as Gentleman of the Bedchamber to William IV, a position which a member of Clan Douglas had occupied intermittently since the late seventeenth century.

Together, they had eight daughters, including:[1] After a period of ill health, Queensberry died at his home at St James's Place, London in December 1837.