From the Mercat Cross at Brechin in 1715, he proclaimed James Francis Edward Stuart, son of James VII and known as the "Old Pretender", as King James VIII. Panmure went on to fight at the Battle of Sheriffmuir in November of the same year.
Lord Panmure was a Privy Councillor to King James VII (ruled 1685–1688), and despite being a Protestant, continued to support James after he was exiled by the Revolution of 1688. He was an early supporter of the Jacobite cause, which aimed to restore James and his successors on the thrones of England and Scotland.