Coffin was one of the leading mariners and traders in the whaling industry. Coffin and two of his sons, Gilbert Coffin and Zenas Coffin, operated a Nantucket based whaling firm during the late eighteenth and early nineteenth centuries called Micajah Coffin and Sons. Their firm conducted business dealing in whale oil, candles, potash, and supplies to Nantucket. Their firm not only conducted business in eastern United States ports, but also did so in the West Indies, France, Nova Scotia, Brazil, and England. Their firm had great success and laid the foundation for Zenas Coffin's future fortune which he later used to enrich the island.
