William McLellan Jr. (1776-1844) was one of the captains who commanded the brig Boxer during her time in mercantile service, and after her capture by the U.S.S. Enterprise near Portland in September 1813. The Boxer originally was a British vessel.

John Brewster Jr., who painted the portrait and who was deaf, grew up in Hampton, Connecticut. He moved to Maine in 1795 and worked as a portrait painter throughout New England.