 Dunn was born in Newport, Rhode Island, where he married Ann Atkinson on November 1, 1754.In 1762 he apparently enlisted in the New York Militia, and in 1765 he was made freeman of New York City, where he worked from 1759-1776 as a silversmith with his shop on Crown Street.In an invoice of January 28, 1775, he billed Philip Schuyler for making 9 gold mourning rings.