Evidently began his career in Boston and then moved to London (c. 1766-68). Traded in association with his brother Henry and his nephew and apprentice Henry Jr. Signed petitions against the Boston Port Bill and the Intolerable Acts (1774). Friend of Josiah Quincy, Jr. and Jonathan Williams, Jr. Established business connection with Silas Deane in France. Returned to America, possibly under pressure from British authorities (c. January 1777).
Son of Edward and Abigail (Coney) Bromfield of Boston.