Popular misconception holds that River Phoenix was set to play the lead before tragically dying on the L.A. sidewalk. This is not entirely accurate. Phoenix was a big fan of the book, and as the film version entered various stages of readiness he was always the front runner. However, prior to his death, he had declined the role due to a combination of feeling he was too old to play a 15 year old, and trying to broaden his range with more adult roles.
After being nominated for an Oscar for Running on Empty (1988), MTV asked River Phoenix what he wanted to do next. He responded by pulling out a beat up paperback of "The Basketball Diaries" and stated "I wanted to play Jim Carroll." Later, the Los Angeles Times declared, "River Phoenix may have wanted it too much." Leonardo DiCaprio was a fan of Phoenix's.
Many links to The Sopranos - Lorraine Bracco (Dr Melfi) plays Jim's mom. Michael Imperioli (Christopher Moltisanti) plays the friend who dies of Leukemia. Vincent Pastore (Big Pussy) is the guy that gets vomited on whilst on the ferry.
Stephen Lang was offered the role of Jim's Basketball Coach named Swifty in the script. Lang declined citing the misrepresentation of the book in the script. The part was subsequently toned down as a result.