Robert Pigot was born in London, England in 1720. His two brothers were George Pigot, 1st Baron Pigot, Governor of Madras, India and Admiral Hugh Pigot, Commander-in-Chief of the West Indies fleet. In 1758 Pigot was Major in the 10th Regiment of Foot. In 1764 he was Lieutenant Colonel. From 1769 to 1775 he was the commander of the 38th Regiment of Foot. He also served as a Member of Parliament for Wallingford from 1768 to 1772. He was appointed Warden of the Mint from August, 1771 until his death.