A lot of young women — or former young women — may disagree with me, but for a while there Zac Efron came off as a poster boy for the following notion: that it’s possible to be too good-looking to be a movie star. In the “High School Musical” films, of course, he was all mussy-coiffed, aqua-blue-eyed charm — a wholesome hunk who knew how to dance, and when he wasn’t dancing knew how to micromanage his charisma so that it fell right on the cusp between dewy and sexy. He was a classic teen idol — he looked like Sean Cassidy with hair gel — and when you’re sitting on top of that world, surrounded by screaming fans, it always seems, at least within the entertainment industry, like you can conquer anything.

It was all but forgone that Efron would get a crack at movie stardom, and he did, but when that happened it was in winsome “crowd-pleasers” like “17 Again,” “Charlie St. Cloud,” and “The Lucky One.” Right away, audiences saw the downside of his teen mystique: He could play the beautiful and thoughtful boy next door, but as an actor, he lacked force and heft and danger. He didn’t know how to smolder. He was so flatly earnest that for all his likability, he came off as a bit of a lox. His looks began to seem like a limitation, maybe even a trap, because their effect was to emphasize a certain underlying passivity. It’s the Vincent Chase principle: If you look like Zac Efron, the whole world comes right to you, so why do you have to do anything — like, you know, act?

But where many a former teen idol has slipped into oblivion, doomed by the cruel calculus of their lightweight beauty, Efron proved to be smarter than that — more chancy and game, and more inventive, too. He’d shown a flair for self-mockery as far back as “Hairspray” (2007) and his own guest appearance on “Entourage” (2009), but the real turning point came in a movie that virtually no one saw outside of Sundance: “Liberal Arts” (2012), Josh Radnor’s savvy and underappreciated college comedy. Cast as a mystical hippie-stoner pest in a wool cap, Efron was all but unrecognizable — and he stole every scene. The hunk, it turned out, had an inner demon who was an ace cutup. He didn’t just know how to make fun of himself. He was good at it. He was funny. And that’s where a door opened.

It was kismet, perhaps, that the one holding the door was Seth Rogen, in his new role as foreman of an exuberant new movie factory to rival that of Judd Apatow. Along with his shifting team of associates (notably his writing and directing partner Evan Goldberg, plus director Nicholas Stoller), Rogen has spearheaded and starred in five swing-for-the-fences comedies: “This Is the End” (2013), “Neighbors” (2014), “The Interview” (2014), “The Night Before” (2015), and the current “Neighbors 2: Sorority Rising.” In both the “Neighbors” films, Efron has been nothing less than a spark plug of hilarity.

As Teddy Sanders, he’s playing the Peter Pan of the beer-pong-and-threesome brigade, the frat bro who never wants to grow up. And in “Neighbors 2,” where Teddy has grown up and now finds himself, in his mid-twenties, corralled into that demo known as “old,” Efron just deepens the joke of his original performance. His Teddy, who’s been coasting his whole life, is a blitzed innocent — a wizard at math, but only as long as he’s toting up the price of a shipment of weed. With no job and no future, he becomes guru to Shelby (Chloë Grace Moretz), who’s trying to launch her own makeshift sorority of bohemian party girls. But it’s really Teddy who’s getting educated. When he’s told that the frat-house credo “bros before hos” is a sexist concept, Efron does a priceless double take: You see him processing the idea, truly taking in its meaning, and then — in a comic flash — evolving.

But that doesn’t mean the aging bro no longer has it. Ultimately, he comes over to the side of Mac and Kelly (Rogen and Rose Byrne), who are desperate to sell their house next door. And when Teddy, as part of their scheme, has to create an epic diversion at a tailgate party, he does what he does best: oils himself up — with the only substance on hand, hot chicken grease — and performs a go-for-broke hip-hop Spring Break flexing-abs dance number. It really does stop the show. The comedy is that Teddy, as Efron plays him, takes his own appeal so for granted that he infuses every gyration and hand-stand with the ticklishly blasé, “I got this” aplomb of someone who knows he’s grown way past this stuff. Teddy knows it, and Efron knows it, too. That’s why he’s now in the unlikely position of standing taller than ever. He has one more movie coming out this summer, the high-concept rom-com “ .” and with any luck it will let him do more of what he’s now proved himself to be terrific at: acting smart about playing dumb about looking like he does. There have been a lot less good recipes for stardom.