NEW YORK—“They keep telling people it’s the 10th anniversary, but it’s the fourth season, as far as I’m concerned,” says Howard Stern, who joined America’s Got Talent as a judge in 2012.

That’s what you’d expect Stern to say.

But he adds quickly that with “AGT” launching what everyone but Stern would consider its 10th season (Tuesday at 8 p.m. EDT on NBC), he’s having a ball with fellow judges Howie Mandel, Heidi Klum and Mel B.

“I may be the most important judge in the history of the world, but secretly I’ll tell you, I’m glad they’re there,” he confided in a recent interview.

Everyone remembers the uproar when Stern was brought aboard this family-friendly talent competition: Wasn’t he a legendary “shock jock,” a bad-boy superstar on SiriusXM Radio who would say anything to get a reaction?

Maybe, but Stern, now 61, thought he would make an ideal judge, that his long show-biz career — wasn’t he the King of All Media? — would serve him well in evaluating each act.

More to the point: He was already a big America’s Got Talent fan.

“It helps when it isn’t just a paycheque for a judge, when they were a fan of the show even before they were getting paid to be on it,” says Jason Raff, an executive producer of the show since its premiere in June 2006.

“It’s a hard show to judge,” he says, noting its lack of any rules; any type of act with any number of performers of any age is welcome.

Mandel was also a devotee of the show before he joined the judges’ panel in 2010.

“I watched every episode for the four years before that,” he says. “Whatever you see me saying and doing is what I was doing from the couch in my living room, in my underpants, before. Now I have the best seat in the house.”

And though he has to wear pants, “the show provides them,” he adds with a laugh.

If the judges are having a good time, host Nick Cannon is having a blast.

“I figure I’m the guy who’s having the most fun,” says Cannon, the show’s ringmaster since 2009. “It’s the best summer job ever, even though there’s a lot of responsibility.”

Responsibility that includes overseeing four opinionated, outspoken judges, plus an anything-can-happen string of acts — which, later in the season, translates to the stage at New York’s Radio City Music Hall.

“It looks like it’s all in my hands, but the producers and the crew do such a great job,” says Cannon. “There are seven people in my ear screaming while I’m having a good time, reacting to each moment to keep the show going.”

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But it isn’t all fun and games, even for the judges; careers are in their hands, and they know it.

“I thought I would do one season, then: ‘The joke’s over, I did it, Howard Stern on a family-friendly show, ha-ha-ha.’ But I ended up enjoying it, and, I swear to you, I take my role on it so seriously!”

He thinks that’s evident to viewers.

“After the first year, people decided, ‘Well, the guy’s thoughtful, he’s constructive. He wasn’t sitting there beating people over the head with a stick.’ You might think that Satan has no feelings, but it turns out Satan’s very, very sensitive: I have the thinnest skin ever. If someone criticizes me, I totally fall apart. So I keep that in mind on the show.”

Meanwhile, he figures he has proven to everyone, including himself, that he can be a team player.

“That was a big ego adjustment for me. I’m so narcissistic that I think my opinion is the only thing that counts, and I really had to put that in check. Sometimes it’s difficult to sit there while Heidi, Mel and Howie do their thing. But that’s the beauty of it. And I particularly like when we argue about talent. I think that’s so interesting.”

Stern knows the choices he makes on the show can help launch a star or dash a lifetime of striving for stardom. He says he’s awakened in the middle of the night after a broadcast, worried that he made the right decision.

“I’m obsessed with getting things right,” he explains. “I recently started painting. I know I’ll never be great. But I’m so obsessed with being a really good painter. So even a hobby becomes like work: I’ve got to be good at this! I can’t stand being so bad at it!”

What does he paint?

“I’ve painted a series of watercolours of flowers for my wife’s office,” he reports.

Watercolours?! Flowers?! That just doesn’t sound like Howard’s style.

“I know,” he laughs. “It shocks the hell out of people. But after I was hired on a family-friendly TV show, there was nothing else shocking left for me to do.”