WilliamJohnson (December 17 or December 27, 1771 - August 11, 1834) was a state legislator and judge in South Carolina, and an Associate Justice of the United States Supreme Court from 1804 to his death in 1834.
Johnson followed in his father's footsteps, representing the city of Charleston (and the nascent Republican party) in the state's house of representatives from 1794-1798.
Johnson was appointed an Associate Justice of the United States Supreme Court by Thomas Jefferson in 1804, as the successor of Alfred Moore.