A native of Crystal City, Missouri, Bradley was a Rhodes Scholar and basketball player at Princeton University, serving as captain of the US Olympic basketball team in 1964 and received the James E. Sullivan Award, presented to the United States' top amateur athlete, in 1965. After graduating from Princeton and playing professional basketball briefly in Italy, he was recruited by the New York Knicks of the National Basketball Association. In ten years playing forward for the Knicks, "Dollar Bill," as he was known, scored a total of 9,217 points and won two NBA championships, in 1970 and 1973. Bradley retired from basketball in 1977. In 1982, he was inducted into the Basketball Hall of Fame, and in 1984 the Knicks retired his number 24 jersey.
In 1978, Bradley was elected to the United States Senate from New Jersey. He served in the Senate until his retirement in 1996, serving on the Finance Committee, the Energy and Natural Resources Committee, the Special Committee on Aging, and the Select Committee on Intelligence.
Bradley ran for the Democratic Presidential nomination in 2000, but lost to Vice President Al Gore. On January 6, 2004, Bradley followed Gore's lead and endorsed Howard Dean for president.