Thomas Elder served as Chief Magistrate of Edinburgh during three separate periods between 1788 and 1798, with his second term being particularly significant due to political unrest. He played a crucial role in suppressing the British Convention in December 1793, personally leading efforts to disperse radical "Friends of the People" gatherings and arrest their leaders, including breaking up Maurice Margarot's procession in January 1794. For his vigorous defense against democratic agitation, the Town Council awarded him a piece of plate, and he was appointed First Lieutenant-Colonel of the Royal Edinburgh Volunteers in 1794. In 1795 he became Postmaster-General for Scotland in recognition of his services. Despite declining health, he accepted a third term as Provost out of duty, but the strain proved fatal—he died in May 1799 at age sixty-two. Elder was also instrumental in planning the rebuilding of the University College and was honored with a portrait by Sir Henry Raeburn for the University library. A wine merchant by trade, he was known for his integrity, firmness, and unpretentious manner.