The Waterloo Hawks were founded in 1948, playing in the National Basketball League. In 1949, the National Basketball League was absorbed by its rival, the Basketball Association of America, forming the National Basketball Association; the Hawks were thus a founding member of the NBA. In the 1949–1950 season, their first and only one in the NBA, they finished 19–43, fifth out of six in the Western Division. The Waterloo Hawks are of no relation to the current-day Atlanta Hawks franchise; at the time of Waterloo's existence in the NBA, the latter franchise was based in Moline, Illinois as the Tri-Cities Blackhawks (and moved to Milwaukee when Waterloo's franchise folded).
The National Basketball Association contracted after the 1949–1950 season. The league went from 17 teams to 11 before the 1950–1951 season started. Midway through the 1950–1951 season, the Washington Capitols folded as well, bringing the number of teams in the league down to ten.
Meanwhile, the National Professional Basketball League was formed around the former NBA teams, with teams added in new larger markets. The charter teams were the East Division: Sheboygan Redskins (Former NBA), Anderson Packers (Former NBA), Louisville Alumnites and Grand Rapids Hornets. West Division: Denver Refiners/Evansville Agogans, Saint Paul Lights, Kansas City Hi-Spots and Waterloo Hawks (Former NBA).