During the American Revolution he remained a Loyalist. A few days after the declaration of independence he left New York City for Perth Amboy for his safety. He returned to New York City after the British reoccupation. On 1 May 1777 he was appointed the head of the military court of police and on 17 July the superintendent of all imports and exports. In 1780 he was appointed lieutenant governor of the Province of New York. In 1783 he was part of the delegation that met with George Washington at Tappan. He was the acting governor from April 1783 to November. Elliot sent his family back to Scotland on the "Nunsuch" on July 9th, and then he left for Scotland in December 1783. He held no public offices in Scotland and died at home on 25 May 1797 at Mount Teviot, Jedburgh, aged 68.