The 26-year-old heart-throb plays fraternity leader Teddy who, much to the consternation of the couple next door, oversees a series of increasingly raucous house parties fuelled by booze, testosterone and the occasional magic mushroom.
Unlike Teddy, Efron's coming of age was carried out in the full glare of the spotlight, having found fame in 2006 as wholesome schoolboy Troy Bolton in smash hit High School Musical.
He'd started acting while still at school, performing in theatre shows before landing his first small TV jobs in 2002 in his early teens.
Disney's High School Musical proved a game changer, and the subsequent ups and downs of the actor's life - including a reported stint in rehab for substance abuse last year - have been well documented.
"I was really blessed early on, but then you're sort of under that microscope," Efron admits.
"It's a little bit more embarrassing because, you know, it's out there for everyone to see... But I don't regret anything. I'm still very grateful."
The actor generated headlines again recently when he was photographed at a basketball game in Los Angeles with actress Halston Sage, who plays Teddy's love interest Brooke in the new film.
With all Efron's experience, you'd expect him to be an expert at answering personal questions, but when talk turns to his love life, he seems unsure.
Asked if he's single, the friendly and surprisingly low-key star replies: "I... yeah... sort of."
At the mention of Sage, he looks even more awkward. "I... can't confirm or deny... I need to figure out what to say."
"Single and ready to mingle!" one of his team offers, to which Efron responds with a laugh: "Yeah."
The actor is much more comfortable talking about Bad Neighbours, which also stars Knocked Up funny man Seth Rogen and Bridesmaids actress Rose Byrne as the new parents living next door.
Since flying the Disney nest in 2008 (when the third and final High School Musical film was released), Efron expanded his repertoire by playing a US Marine in 2012 drama The Lucky One, and Nicole Kidman's toy boy lover in thriller The Paperboy.
When he received a call from "comic genius" Rogen, who also co-produced Bad Neighbours, the California-born star was "stoked".
"I usually try not to talk about potential movies, I'm superstitious that way, but I was too excited about this. I was on the phone with my mom, dad, brother and friends before I even heard the pitch."
The writers have revealed one of the reasons they wanted Efron to play Teddy was because he'd be "the last person you'd want to see shirtless on the front lawn talking to your wife".
Indeed, the actor spends a significant proportion of the film with his gym-honed body on show.
But Efron says there were days when he didn't feel like stripping off.
"Seth would be like, 'Dude, just take it off' - I had no choice!" he teases. "It was constant. I found that most of the time the camera wouldn't even be on. They would just make me do it and laugh."
When Rogen and Byrne's characters report the Delta Psi Beta fraternity to the police for their wild antics, a turf war kicks off.
Both sides resort to increasingly drastic measures in a bid to force each other out - from honeytraps and spy cameras, to vandalism and sword fights with sex toys.
There were moments when Efron feared the crudity and comedy boundaries had been pushed to the limits.
"Every single day was crazy. No matter what we were doing, it seemed like we took it one step too far, and then we'd go another step past it," he smiles.
But he isn't worried about what High School Musical fans will make of the near-the-knuckle comedy.
"I think they're two completely different things. I'm blessed to have both opportunities.
"I think it's a good film, so I'm excited for those people to see it," he adds. "And they're all grown up, anyway."
n Bad Neighbours is released in cinemas today.