Thompson worked as an industrial relations representative for Ford Motor Company during law school. After graduation he worked as an attorney for Monsanto Company in St. Louis until 1977. That year he joined the law firm of King & Spalding in Atlanta, Georgia. He left the firm in 1982 for four years as U.S. attorney for the northern District of Georgia; however, he returned and was made a partner in 1986. He left King & Spalding in 2001 to return to the Justice Department as Deputy Attorney General.
