Hollywood is an impatient place. When it finds a promising young actor, its instinct is to thrust him into full-scale stardom before he outgrows youthful roles. The inexperienced object of this mismanagement generally finds himself with minimal craftsmanship as a performer, a resume full of misfires and fast-dimming fame. Call it the Matthew McConaughey Syndrome.

Zach Braff, Ashton Kutcher and Frankie Muniz are cases in point, but the current Exhibit A is Jon Heder. He scored a magnificent junior varsity touchdown with his first movie role in “Napoleon Dynamite” and now is being promoted like an NFL star quarterback. It’s no favor to him to thrust Heder into the big leagues before he’s prepared, and as the lame, formulaic “School for Scoundrels” demonstrates, it’s a disservice to audiences, too.

Heder plays Roger, a meek New York City parking-meter attendant who tootles around the streets in a three-wheeler, apologetically doling out tickets and knuckling under to the hoods that shoot out his vehicle’s tires, steal his shoes and make him tear up their citations. Roger is the butt of pranks and teasing at work, and a tongue-tied stumblebum when he tries to talk to his cute neighbor, Amanda (Jacinda Barrett).

Fed up, he enrolls in a top-secret assertiveness course taught by Machiavellian rogue Dr. P (Billy Bob Thornton). The imposing Dr. P breaks his students down before building them up.

“Losers have tried and failed,” he sneers. “You haven’t even tried.”

He teaches them to unleash their “inner lion” and use whatever underhanded means is necessary to take what they desire. When he learns that Roger wants Amanda, the hypercompetitive Dr. P charms her and challenges Roger to win her away.

Thornton is deliciously obnoxious as the suave scoundrel, systematically destroying Roger’s personal and professional life, and double-dog-daring him to do something about it. You’re never quite sure whether the character is an extra-gruff life coach prodding his clients to stand up for themselves, or a psycho. Billy Bob’s bully is funny, frightening, magnetic, mysterious, and he makes an impression so much bolder than Heder’s that he turns the movie head over heels.

Heder’s performance is an exercise in desperation, his love-me-nerd neediness wearing thin in instants. When he attempts to project romantic yearning, he simply looks constipated. He can’t give the character the kind of edgy neurosis that’s interesting; he’s just a repressed post-nasal drip. It’s the audacious villain of the piece who gives the film life.

There isn’t a lot in this peculiar and unsatisfying movie that is worthwhile – even an extended Ben Stiller cameo falls flat – but every moment worth remembering belongs to Thornton, one of the premier character actors of his generation. It took him a lot of years to attain that position, but it was worth the wait.