Cornelius Harnett was born in Ireland and immigrated to Chowan County, North Carolina by 1720. In December 1725 after Governor George Burrington was removed from power and replaced by Richard Everard, the former governor and Harnett led a riot against Everard in Edenton. Soon after the riot, Harnett left Edenton and moved south to Brunswick, where he operated a ferry. In 1730 when Burrington again became governor, Harnett became a member of the Governor's Council, serving until 1732. Harnett later served as a justice of the peace for Bladen County in 1732 and as a justice of the peace for New Hanover County from 1736 to 1741. From 1739 to 1740 he was also the sheriff of New Hanover. Harnett died in New Hanover in 1742.