Her paternal grandparents were Sir Robert Douglas and Margaret Erskine, a former mistress of King James V of Scotland, and her maternal grandparents were George Leslie, 4th Earl of Rothes and Margaret Crichton, an illegitimate daughter of Princess Margaret, the youngest sister of King James III.
Her father succeeded to the Earldom of Morton in 1588 as the 6th earl upon the death of his kinsman, Archibald Douglas, 5th Earl of Morton.