As Berger, the brash leader of the hippie tribe in the revival of “Hair,” which opened Tuesday at the Al Hirschfeld Theatre, Will Swenson spends a lot of time onstage being, as he describes it, “a loose cannon.” That’s an understatement.

Swenson strips down to a loincloth, simulates drug use and sex, likens himself to Lucifer (in the song “Going Down”) and goes Full Monty — and that’s just in the first act.

But offstage, he is quite unlike that extroverted character. This soft-spoken native of Provo, Utah, a former member of the Mormon Church and the divorced father of two young boys, lives far from Broadway’s hustle and bustle, on a quiet, leafy block of Inwood.

“I’m fairly shy and modest,” says the handsome, green-eyed, 6-foot-2 actor. “I grew up conservatively. But I do allow this bawdy character [Berger] to take over, and my ass is out there every night — literally.”

It’s certainly one of the most high-profile roles the actor has had since coming to New York eight years ago.

Swenson made his Broadway debut in 2005 in “Brooklyn the Musical” and went on to stints in “110 in the Shade” and the ill-fated “Lestat.” He was last seen in a long blond wig, playing rocker Stacee Jaxx off-Broadway in “Rock of Ages” (which opens on Broadway April 7).

“I had to choose between two Broadway roles — Stacee and Berger — which is a pretty good place to be as an actor,” Swenson says. “In the end, I’d put a lot of my heart and soul into ‘Hair’ over the course of three years.” (He was in the two Public Theater revivals of the musical in 2007 and 2008.)

When Swenson isn’t dancing and singing seven days a week, he’s with his sons, Bridger, 5, and Sawyer, 8, who split time between him and their mother, who lives a couple blocks away.

The boys’ bunk beds and toys claim the rental apartment’s only bedroom, and their art covers an entire wall in Swenson’s makeshift living room/sleeping area. Also hanging there is a New York Giants poster given to him by Bridger. “I actually like the Denver Broncos, but he was so excited to get me something that had to do with football.”

A large, flat-screen TV dominates another wall — Swenson likes “Lost” and “Friday Night Lights”– and an extensive collection of DVDs are shelved above the bed, among them a Bon Jovi concert DVD (“research for ‘Rock of Ages,’ ” he says).

Photos and props from his various shows also line the shelves. The pieces include a rubber hamburger (“My sister got me that when I got the part of Berger”), a well-worn cowboy hat from “110 in the Shade” and several items from the Mormon musical “UTAH!” (“I broke my arm doing that show”).

They are mixed in with film paraphenalia, including an award for the 2004 movie “Sons of Provo,” a mockumentary about a Latter Day Saints boy band that Swenson co-wrote, directed and starred in.

Lining the hallway are cast-autographed posters of productions that Swenson has been in — including tours of “Miss Saigon” and “Fame.” He refers to it as “my blatantly self-congratulatory wall of show posters.”

As for Inwood, where he’s lived since moving to New York, Swenson says, “There’s the Cloisters and lots of parks, up-and-coming restaurants and new families moving in. It’s mellow up here and good for the kids.”

So, what does this responsible family man have in common with the bohemian Berger, besides long hair?

“I don’t like people telling me what I should be,” says Swenson. “I very much relate to Berger’s need to think for himself.”