Russ Tamblyn was a child star, then primarily a dancer. This `dramatic' role fell to him between his memorable assignments in Seven Brides for Seven Brothers and West Side Story. He's not at all bad here (in an badly written and implausible role), but was never able to establish himself as a serious actor, though he continued to work, showing up notably decades later in Twin Peaks.
John Drew Barrymore had just taken up his middle name to distance himself from his legendary father; in earlier roles (The Big Night, While the City Sleeps), he was billed as John Barrymore, Jr. Here he brings off an eerily precise impersonation of Elvis Presley, speaking both in hillbilly accent and in basso-profundo register. (Alas, he does not sing.) It's clear he inherited the family talent, which he was to squander, because he also inherited the predisposition to chemical experimentation.
Jan Sterling seemed destined for a bigger career than she ended up with. The high points of her filmography Billy's Wilder's The Big Carnival/Ace In The Hole being the most impressive of them were behind her, and she was taking secondary roles to the likes of latter-day Joan Crawford ( in Female on The Beach). Here, as a schoolteacher, she not only does a riff on Eve Arden's Our Miss Brooks character, she even looks like Arden.
The late fifties were the blazing noon of Mamie Van Doren's fling at playing third-string sexpot (after Marilyn Monroe and Jayne Mansfield). All Dagmars and platinum hair, she was rarely called upon to display what might have been a comic talent, visible here in fits and starts. Her role as a married nymphomaniac whose attempts at fulfilment absent her husband seemed doomed to disappointment is practically a clone of the part she played in The Beat Generation, a slightly more interesting vehicle that covers much of the same ground as High School Confidential.
High School Confidential remains notable from a view of drug trafficking and the process of addiction that had advanced not a whit since Reefer Madness in the thirties. And of course its view of teen-aged life in the second Eisenhower administration bears not the slightest resemblance to any reality then or now. That said, it's fun to watch.