He was the second son of William Douglas, 1st Duke of Queensberry.
Hon. John Douglas of Broughton (died 1832) was the second son of William Douglas, 1st Earl of March.
He was the son of William Douglas of Egilsay and Marjorie Monteith.
He was the son of William Douglas, 2nd Earl of Angus and Margaret Hay of Yester.
William Douglas was the eldest son and heir of William Douglas of Whittingehame (died bef.
His father, Patrick Douglas, was the second son of William Douglas of Whittinghame.
He was the son of William Douglas of Fingland and Elizabeth (Betty) Clerk.
Born in Peebles, Queensberry was the only son of William Douglas, 2nd Earl of March, and his wife, Lady Anne Hamilton.
He was born at Head of Hillsborough as the son of William Henry Douglas, a Scottish immigrant.
On his father's side he was descended from Sir Archibald Douglas, a younger son of William Douglas, 1st Earl of Queensberry.
