Showbiz manager Shep Gordon, left, and client Alice Cooper in an archival photo from “Supermensch,” a docu-paean by first-time director (and Gordon client) Mike Myers. (RADiUS-TWC)

There are many superlatives lavished on entertainment manager Shep Gordon in the documentary “Supermensch: The Legend of Shep Gordon.” But only one explains why the movie was really made. “Shep Gordon is the nicest person I’ve ever met, hands down,” Mike Myers earnestly tells the camera.

The movie is Myers’s directorial debut, and it feels like elaborate repayment for the ways Gordon has helped the comedian. Gordon does seem like a nice guy, and it’s reassuring to see that nice guys don’t always finish last, even in Hollywood. But the hero worship that powers the movie occasionally feels overblown, if not altogether cloying.

Gordon had an unlikely ascent that began after a failed career as a probation officer landed him at the Los Angeles hotel where Janis Joplin and Jimi Hendrix had also decamped. According to Gordon (whose memories are admittedly a little hazy), it was Hendrix’s idea for Gordon to become a manager and to represent Alice Cooper, with whom Gordon went on to have a lifelong friendship.

In fact, the managing gig was only a cover for Gordon’s drug-dealing business, but at some point, the Long Island native decided to keep to the straight and narrow, and his client list grew to include Pink Floyd (if only for a few days), Luther Vandross and Teddy Pendergrass. In the meantime, he became friends with Michael Douglas, Sylvester Stallone, Emeril Lagasse, Willie Nelson and Tom Arnold, all of whom sing Gordon’s praises in the movie. He also married a Playboy model (though their marriage was annulled soon after), cooked for the Dalai Lama, saved Groucho Marx from financial ruin, shared a cat with Cary Grant and dated Sharon Stone.

All the while, like a good Lannister, he repaid his debts. If someone did Gordon a favor, he never forgot, and if he burned any bridges, they aren’t evident here. Then again, neither of his former wives nor Stone gives interviews.

The movie is at its best when it’s looking at Gordon’s business savvy. He helped invent the Alice Cooper persona, and even placed the ill-fated chicken onstage that launched Cooper’s moneymaking bad reputation. Gordon is also credited as the man who jump-started the celebrity chef trend and managed to make angelic Canadian songbird Anne Murray into a hip star thanks to a perfectly timed photo-op with John Lennon.

But one question remains: How much of this can we believe? When Gordon’s cousin calls him “the most wholesome person I’ve ever known,” it smacks of hyperbole, at best. How wholesome are multi-day benders and Playboy Mansion skinny-dipping? And although Gordon makes a talented and easygoing storyteller, he isn’t necessarily the most reliable source. A story that involves seeing Pablo Picasso turns out to be false, because Picasso had been dead for years by the time Gordon says he saw the painter. Gordon was, he admits, “pretty high” at the time. But the stories — even the dubious ones — are better than the film’s dramatizations; having actors try to re-create scenes from the past is almost never a good idea.

The specter of a really interesting theme floats in and out of the movie, and it deals with Gordon’s loneliness. Here’s a guy who has worked hard and has a long list of celebrity friends to show for it. And yet, he’s still alone, living in Maui in a big house without the companion or kids he always wanted. The movie’s focus on good vibes and high times leaves little room to contemplate the more human story. Regardless, the movie is good-natured and an enjoyable watch. If Myers really just wanted to show his appreciation, he went above and beyond.

★ ★ ½

R. At the Angelika Pop-Up and Avalon. Contains language, nudity, sexual references and discussions about drug use.

About 80 minutes.