William Robert "Slick" Leonard (born July 17, 1932) is a former professional basketball player and coach. A 6'3" 185 lb (84 kg) guard, Leonard played high school basketball at Terre Haute Gerstmeyer High School, where he excelled as a tennis player, as well. He played collegiate basketball at Indiana University, where he hit the game winning free throws to give Indiana the 1953 NCAA championship. While at Indiana, he became a member of Delta Tau Delta International Fraternity.
He was selected with the first pick of the second round of the 1954 NBA Draft. He spent most of his seven-year professional playing career with the Lakers (four years in Minneapolis, and one year following the team's move to Los Angeles), followed by two years with the Chicago Packers/Zephyrs). In his final season as a player, he also coached the Zephyrs. The next year, the team moved to Baltimore; Leonard coached them for one more year.
In 1968, Leonard became the coach of the American Basketball Association's Indiana Pacers, a position he held for nearly 12 years – the last four after the franchise moved to the NBA. For a time, he also served as general manager. Leonard led the Pacers to three ABA championships before the ABA-NBA merger in June 1976. However, the Pacers were nearly gutted in order to meet the financial burdens imposed by the merger, and he was never able to put together a winning team during the Pacers' first four years as an NBA team.
Leonard returned to the Pacers in 1985 as a color commentator, first for television with Jerry Baker, then on radio, where he remains alongside Mark Boyle on WFNI 1070 AM. His trademark phrase is "Boom, baby!" for a successful three-point shot by a Pacers player.
On March 13, 2011, Leonard suffered a heart attack shortly after a Pacers road victory over the New York Knicks. He was later said to be in good condition, but was given an indefinite time to recover, and was filled in for by Pacers TV analyst and former player Austin Croshere.