William Paterson was born in northern Ireland, moved to the United States at age 2, and entered Princeton University at age 14. After graduating he studied law with the prominent lawyer Richard Stockton and was admitted to the bar in 1768.
Paterson became an outspoken supporter of American independence. He was selected as Somerset County delegate for the first three provincial congresses of New Jersey, where as secretary he recorded New Jersey's constitution in 1776.
After Independence, Paterson was appointed New Jersey's first attorney general, maintaing law and order and establishing himself as the best lawyer in the state. He was sent to the 1787 Constitutional Convention in Philadelphia where he proposed the New Jersey Plan for unicameral legislative body with equal representation from each state. After the Great Compromise (for two legislative bodies), the Constitution was signed.
He served as governor of New Jersey and in the New Jersey state senate, where he oversaw the revision and codeification of the entire state legal system. George Washington appointed him associate justice of the United States Supreme Court in 1793.