His father Thomas Clark realized that he had a natural grasp for math so he hired a tutor to teach Abraham surveying. New Jersey returned him twice more from 1780 to 1783 and from 1786 to 1788. He was a member of the Committee of Public Safety.
Early in 1776 the New Jersey delegation to the Continental Congress was opposed to independence from Great Britain. Clark married Sarah Hatfield in 1748 with whom he had 10 children. However there was one instance when Clark did bring them up and that was when one of his sons was put on the prison ship Jersey notorious for its brutality.