Joseph Gilman was the son of Reverend Nicholas Gilman and Mary (Thing) Gilman. He was born in
Exeter, New Hampshire, on May 5, 1738. He was the brother of minister
Tristram Gilman (1735–1809) and a cousin of
Nicholas Gilman. He was educated in his hometown, and went to
Boston, Massachusetts, at age fifteen to work for a merchant. He stayed there until at least 1760, and in 1761 entered into partnership for seven years with Nathaniel Folsom and Josiah Gilman in Exeter as
Folsom, Gilman and Gilman to keep a store, build ships and make seas voyages. They had extensive dealings in England and the Caribbean. Gilman was married to Jane Tyler, who probably died in 1760, and then to Rebecca Ives (1745-1823) of
Beverly, Massachusetts, in 1763. They had sons Robert (1764-1766) and
Benjamin (1766-1833). ==Public life==