Under President Bill Clinton, Lader was confirmed three times by the U.S. Senate. He served as Deputy Director of the Office of Management and Budget until becoming White House Deputy Chief of Staff and Assistant to the President in December 1993, when "The New York Times" described him as "a longtime friend" of Clinton's. He was a member of President Clinton's Cabinet while serving as Administrator of the Small Business Administration from 1994 to 1997. During Clinton's second term, he was United States Ambassador to the Court of St. James's.