Born in West Simsbury, Hartford County, Connecticut on September 2, 1757, he completed preparatory studies and enlisted as a private in the Connecticut Militia for the Revolutionary War. He took part in several actions, including the Battle of Long Island, and received his commission as an officer. Humphrey continued his military service after the Revolution and was discharged as a major in 1796.
In 1810 he served again as Onondaga Town Supervisor, and he was a member of the New York State Senate from 1811 to 1815. In 1812 he served as Onondaga's Public School Inspector. He resumed farming, and died near Marcellus on August 12, 1831. He was interred in the Old Village Cemetery in Marcellus.