Noble and antiquarian. Born in Edinburgh, the son of the 10th Earl of Buchan, Erskine was raised on the family estate at Uphall in West Lothian. He inherited the title Lord Cardross when his elder brother died in 1747. His younger brother, Henry Erskine (1746 - 1817), was Lord Advocate. He was educated at the Universities of St Andrews, Edinburgh and Glasgow. Erskine accepted a commission in the army in 1762, and was offered the post of Secretary to the British Embassy in Madrid in 1766 but declined because his father was ill. The following year his father died and he inherited the Earldom. Erskine founded the Society of Antiquaries of Scotland in 1780 and supported it financially and added to its collections. Erskine served as the Grand Master Mason of Scotland (1782-84).
He improved his West Lothian estate, but bought Dryburgh Abbey in 1786 and restored it as a romantic ruin, living in the adjacent Dryburgh Abbey House. Erskine died there and was buried in the grounds of the Abbey. With only an illegitimate son, the Earldom passed to his nephew. Before he died, he had persuaded Sir Walter Scott (1771 - 1832) to accept a burial plot in the Abbey grounds. His collection of portraits formed the foundation of the Scottish National Portrait Gallery.
