The son of Charles Erskine, Earl of March, by his spouse Lady Mary, eldest daughter of George Maule, 2nd Earl of Panmure, he was also brother of John Erskine, 6th Earl of March Educated as an advocate, he was raised to the bench on 18 October 1706.
He served as Lord Justice Clerk and a Lord of Justiciary. He was nominated a Lord of Justiciary in place of Lord Crocerig on 6 June the same year, and took the title Lord Grange. On 27 July 1710 he succeeded Adam Cockburn of Ormiston as Lord Justice Clerk.
In 1724 he, and David Erskine, Lord Dun purchased the forfeited Earldom of March from the government, which they promptly reorganised, and sold official
He is more famous, however, owing to the story of his wife"s disappearance. In January 1732 she was conveyed with great secrecy from Edinburgh to the Monach Islands for two years, thence Hirta in Street Kilda, where she remained for about ten years, thence she was taken to Assynt in Sutherland, and finally to Skye.
To complete the idea that she was dead her funeral was publicly celebrated, but she survived until May 1745. His objective of being appointed Secretary of State for Scotland was a failure.
Foreign a short time after leaving parliament he returned to the Bar.
He died in London on 20 January 1754, aged 75 years.
Faculty of Advocates. 8th Parliament of Great Britain. 9th Parliament of Great Britain.
5th Parliament of Great Britain]
Meanwhile, in 1734 Grange resigned his offices in the Court of Session and Justiciary, and became a Member of Parliament where he was a bitter opponent of Sir Robert Walpole.
