Before becoming the 35th president of the United States in 1961, John Fitzgerald Kennedy of Massachusetts served in the House of Representatives and in the U.S. Senate. Kennedy gained national prominence as the junior senator from Massachusetts when he served on the Senate Select Committee on Improper Activities in the Labor and Management Field, which held public hearings to investigate corruption in American labor unions. He also became a best-selling author, winning the Pulitzer Prize for Profiles in Courage in 1957. That same year, he chaired a special committee to choose the Senate's Famous Five. When Kennedy became the Democratic nominee for president in 1960, he chose Senate majority leader Lyndon B. Johnson as his vice-presidential running mate.