He was born in New Bern, North Carolina, the son of the Secretary of the Crown in the colony and grand-nephew of North Carolina governor Arthur Dobbs. Orphaned at the age of eight, he was sent to live with his Dobbs relatives at Carrickfergus in northern Ireland and later followed his cousin Richard Dobbs to the University of Glasgow. During the American Revolution Spaight returned to North Carolina, serving as Aide-de-camp to Major General Richard Caswell at the Battle of Camden Court House.