Spike Lee originally wanted Kobe Bryant to play the part of Jesus Shuttlesworth. While Kobe liked the script, and the idea of working with Spike, he had just finished his rookie year in the NBA (the 1996-97), and had shot several airballs in a brutal playoff loss by the Lakers to the Utah Jazz, and planned a workout program that would help him maintain his strength through the longer NBA seasons (a major adjustment, as Kobe went straight from high school to the pros). So he told Spike the summer of 1997 was too important to spend time making the film, and Spike promptly sought out Ray Allen, who quickly accepted the lead role.
Ray Allen and Spike Lee have had conversations about having a de facto sequel to this film, with Allen saying he would envision Jesus Shuttlesworth nearing the end of a successful pro career (much like Allen himself). As part of his expression of interest in such a project, when Miami Heat players were allowed to wear special jerseys with nicknames or initials as part of an NBA promotion, Allen's jersey said "J. Shuttlesworth" on the back--an image Spike Lee immediately and happily posted to Instagram.
In addition to the multiple coaches and players appearing as themselves, three of Jesus' teammates were played by NBA players at the time of the movie's release, Travis Best, Walter McCarty, and John Wallace. Another NBA player, Rick Fox, played Chick, who shows Jesus around Tech University. As of 2014, Fox has quite a bit of acting roles, but this movie is the only screen roles for Best and McCarty, while Wallace only has one other acting role, in another Spike Lee movie Bamboozled (2000).
The trivia items below may give away important plot points.
For the scene where Jesus and Jake play for the letter of intent, the original script called for Jesus to win 15-0. However, Spike Lee encouraged the actors to play for real. When the contest between Ray Allen and Denzel Washington began, Denzel scored four straight points as the crew whooped and applauded from the sidelines. Allen was furious, and proceeded to score ten points in a row, at which point, Spike Lee declared Allen had won, and the scene (and game) was finished.