Bruce was the son of Thomas Bruce, 2nd Earl of Ailesbury and Lady Elizabeth Seymour, daughter of Henry Seymour, Lord Beauchamp and Mary Capell. In December 1711 he was summoned to the House of Lords through a writ of acceleration in his father"s junior title Baron Bruce of Whorlton. In 1741 he succeeded his father in the earldoms of Elgin and Ailesbury.
Bruce was returned to Parliament for Great Bedwyn in 1705, a seat he held until 1710, when he was returned for both Great Bedwyn and Marlborough and chose to sit for the latter.
Lord Ailesbury married, firstly, Lady Anne Savile, daughter of William Savile, 2nd Marquess of Halifax. They had four children:
Honorary Robert Bruce (d 30 August 1738), married Frances Blackett (d 16 July 1750), daughter of Sir William Blackett, 1st Baronet, of Newcastle-upon-Tyne, without issue.
Honorary
George Bruce (born before 1717). Lady Mary Bruce (1710 – 14 August 1738), married (1728) Henry Brydges, 2nd Duke of Chandos and had issue. Lady Elizabeth Bruce, married (1732) the Honourable Benjamin Bathurst, son of Allen Bathurst, 1st Earl Bathurst, without issue.
After his first wife"s death in July 1717, Lord Ailesbury married, secondly, Lady Juliana Boyle, daughter of Charles Boyle, 2nd Earl of Burlington.
They had no children. They had one daughter:
Lady Mary Bruce (d 5 November 1796), married (1757) Charles Lennox, 3rd Duke of Richmond, without issue.
His Scottish lordship of Kinloss was subsequently determined to have devolved upon James Brydges, 3rd Duke of Chandos, who, however, did not claim the title. She died in January 1803, aged 82.
1st Parliament of Great Britain. 2nd Parliament of Great Britain. 3rd Parliament of Great Britain.
