American International Pictures originally offered the role of Max Frost to noted folk singer-songwriter Phil Ochs, who was known at the time to want to branch out into film work. However, after reading the screenplay, Ochs rejected it, stating the story presented the youth counterculture of the 1960s in a badly distorted light.
"The Shape of Things to Come", written by Barry Mann and Cynthia Weil, was a #22 chart hit for Max Frost and the Troopers (a "studio group", made up of session musicians) in 1968. In 2006, it was featured in commercials for Target Stores.
Max Frost (Christopher Jones) asks Billy Cage (Kevin Coughlin) how long he thinks he is going to live and he replies "30, man." Coughlin was later killed as a pedestrian struck by a speeding car just five weeks after turning 30.