Lawyer and politician. The son of John Elphinstone, 3rd Lord Balmerino (1623 - 1704), Elphinstone gained a considerable reputation as a lawyer. He was appointed to the Privy Council of Scotland in 1687 by King James VII (1633 - 1701). He married twice; firstly in 1672 to Christian daughter of Hugh Montgomerie, 7th Earl of Eglinton (1613-69) and secondly, in 1687, to Anne daughter of Arthur Ross, the Bishop of St Andrews.
He opposed the Union of 1707, but never-the-less served as a Scottish Representative Peer between 1710 and 1713. He also served as Governor of the Mint and Sheriff of the County of Edinburgh. A Tory and a Jacobite, he collaborated with George Lockhart of Carnwath (1673 - 1731), who had married a niece of his first wife and was Tory leader in Parliament. In 1712, the pair managed to bring about the passage of an Act which restored lay patronage in the Church of Scotland. In his later years, Elphinstone worked secretly to promote the Jacobite cause.