Judd Apatow’s coronation as Hollywood’s new king of comedy tastes a little bittersweet to him. Apatow is not just the director and writer of two of the biggest comedy hits of the past few years, The 40-Year-Old Virgin and the new Knocked Up, but he also produced Anchorman: The Legend of Ron Burgundy, and Talladega Nights: The Ballad of Ricky Bobby, both starring Will Ferrell and both huge hits in America. A slew of other comedies in which Apatow is the main creative engine will hit cinema screens soon, including Superbad, co-written by one of his regulars. Woody Allen, move over.

Apatow’s humour, well meaning but usually filthy, has clearly hit a nerve with audiences. The films he has directed, produced and written in the past three years have taken nearly $900m at the box office. Featuring loveable geeks who only want to be appreciated for who they are, they have made the most unlikely matinée idols out of Seth Rogen, Apatow’s 26-year-old alter ego, who plays the lead in Knocked Up, and Steve Carell, star of The 40-Year-Old Virgin. The simple but hilarious premise of Knocked Up is that Katherine Heigl, best known as Izzie, the beautiful blonde doctor on the television series Grey’s Anatomy, gets pregnant after a drunken one-night stand with Rogen’s character – a schlubby, overweight, pot-smoking loser who lives with his pot-smoking loser friends. Between bong hits and ribald jokery, they are trying to set up a website that will show people actresses appearing nude in movies. Perfect husband material.

Apatow, sitting poolside with his family at the Hollywood Roosevelt Hotel last week, getting ready for the premiere of Superbad a couple of hours later, is certainly not complaining. But the problem for the 39-year-old, who looks like a cross between Bill Murray and WC Fields, his squishy, hangdog, bearded face dominated by a marvellously effusive nose, is that he never wanted to be a writer, director or producer. His success, which has been hard won, considering he arrived in Hollywood when he was just 17, was born from the painful realisation in his early twenties that he was never going to achieve what he had yearned for since he was a kid. “The only dream I ever had was to be a stand-up comedian,” he says. “But I slowly realised the other comedians were way funnier and much better performers than me. If you’re opening for Jim Carrey, it’s hard to walk away thinking, ‘I’m going to be able to be better than that.’ I didn’t have anything to say. I didn’t have any life experience to draw on.”

For Apatow, becoming a stand-up comedian was actually more than a dream. It was, from the time he was eight or nine, a geeky obsession. “Before VCRs, I would tape the television series Saturday Night Live with an audio-cassette recorder and then transcribe it,” he recalls. In his teens, he got a job as a dishwasher in a comedy club; then in high school on Long Island, he started a radio show called Club Comedy so he could interview comedians. “It was just an excuse to talk to them, to get face-to-face with them and ask, ‘How do you do this? What’s the process?’” he says. “I was really fascinated with how you became that person.” He interviewed more than 50 comedians, including people who would later become household names, such as Jerry Seinfeld, Jay Leno, Martin Short and Garry Shandling.

“I tricked them into thinking a real journalist was going to show up,” he says. “Some of them were shocked when this child walked in with an enormous tape recorder that didn’t work very well. I even convinced some of them to do it twice. I remember Jerry Seinfeld saying, ‘Why would we do it again?’ And I said, ‘Well, people do The Tonight Show more than once.’

“One of the best pieces of advice I got was that it takes seven years to find yourself as a comedian – which made me incredibly patient. So when I started doing stand-up, I didn’t care that I wasn’t funny because I thought, ‘Oh, this takes seven years.’” Luckily, Apatow had begun writing for other people, including Roseanne Barr. “So, I’m going to sit in my house and write five or 10 pages of jokes for Roseanne a week, and she’s going to send me 800 bucks?” he says. “I thought, ‘This is the best job ever’ – sitting in my living room and writing jokes as if I were an overweight, middle-aged housewife.” As easy as Apatow found it to write from other people’s perspective, he found it almost impossible to write from his own. “I didn’t have the balls to write anything personal. That’s part of why I quit stand-up; I just didn’t think I was that interesting.”

After moving to LA in his late teens, he befriended and started working with people who were to become some of the biggest names in comedy. He lived with Adam Sandler for a while, wrote jokes on the side for Carrey, and he and Ben Stiller put together a comedy sketch show, The Ben Stiller Show, that actually made it onto television. When that was swiftly cancelled, Apatow was taken on by Shandling as a writer on The Larry Sanders Show, in which Shandling played a misanthropic talk-show host. “I would watch Garry, and he would be so confessional in his work,” says Apatow. “I always loved confessional musicians like Loudon Wainwright III [who appeared in The 40-Year-Old Virgin and provided much of the soundtrack for Knocked Up] and Warren Zevon, so it slowly made me realise, ‘To do good work, you’ve really got to go there and give it up.’”

Yet Apatow says it wasn’t until one of the episodes of Freaks and Geeks, the highly acclaimed TV show he co-produced with Paul Feig – which was, to Apatow’s fury, cancelled after just 12 episodes – that he found a way of tapping into his own psyche. “There was a sequence with this nerdy character, Bill Haverchuck,” Apatow recalls. “You see that his after-school routine is that he makes a grilled cheese sandwich and has a glass of milk and a piece of cake, all while watching The Dinah Shore Show on TV. That’s what I did every afternoon for years when I was a kid, and it’s a really powerful sequence, funny and sad. Jake Kasdan, who directed a lot of the episodes, said, ‘Well, that’s the most personal and the best thing you’ve ever done.’ So, I slowly started to find ways to be revealing in my work.”

The professional setbacks Apatow had to deal with, however, including losing a battle over the scriptwriting credit on Jim Carrey’s The Cable Guy in 1996 and the cancellation of both Freaks and Geeks and his next series, Undeclared (both by the same Fox executive), took him to the edge of psychological and physical breakdown. After The Cable Guy, Apatow had an anxiety attack and holed up in a hotel in Chicago, unable to get on a plane. After Freaks and Geeks was cancelled in 2000, he ended up in hospital with a herni-ated disk. “We felt like a band in the middle of a classic album, and someone was pulling the plug at the studio.” Apatow became notorious in Hollywood when he sent the executive who had cancelled the shows a framed copy of a page from Time magazine that put Undeclared in its list of the 10 best TV shows, along with a note of hilarious crudity. Apatow has since won sweeter revenge by continuing to work with many of the actors and writers from those shows. They have become part of his productive comedy stable, with an astonishing seven films set for release in the next 18 months.

It was only when Apatow found a way of bringing his anxieties and neuroses into his work that he discovered his comic touch. Much of The 40-Year-Old Virgin, which he co-wrote with Carell based on an idea of the actor’s, is drawn from what Apatow remembered of his own dating life. “On one level, it’s a broad comedy, but it’s written from a very intimate place of my own anxieties,” says Apatow. “I’ve never waxed myself, but I am a hairy man and I’ve thought about it. The only reason I don’t is that I’m so hairy, there’s really no dividing line between my chest hair and my back hair. It’s all like a coat, like a dog.” And much of Knocked Up is directly taken from Apatow’s decade-long marriage to the beautiful and extremely funny actress Leslie Mann. As Apatow and I are talking, Mann is being made up for the evening’s premiere of Superbad in the patio doorway of the adjoining hotel room. Mann played the fabulously drunk driver in The 40-Year-Old Virgin, and she is Heigl’s uptight older sister in Knocked Up. She and Apatow have two young daughters, who also appear in Knocked Up.

Like Apatow a decade ago, Rogen’s character in Knocked Up has some fast growing-up to do. “I had children and suddenly I couldn’t sleep until 2pm any more, and I couldn’t lie in bed all day and watch an entire season of MTV’s The Real World,” he says, with evident regret. “I always think so much of my life is my wife having to deal with me, having to walk through this maze of my problems.” But what’s also unusual and refreshing about Apatow’s hapless heroes is that they’re so remarkably well intentioned. “I always relate to guys who feel goofy or unattractive or insecure,” Apatow says, “who feel they have value but don’t quite know how to get that across and are afraid people will never see it. Some people who see Knocked Up don’t understand why Katherine would date Seth, which shows you how the world is set up. To me, he’s a smart, funny, adorable guy who is just in a period of transition: he’s trying to delay adulthood. Why is it shocking that a guy who doesn’t look like George Clooney gets a gorgeous woman? It happens. Most beautiful women are married to goofy guys.”

As I say goodbye to Apatow, whose burgeoning paunch is covered by a livid purple Tommy Bahama T-shirt, fierce plaid shorts topping short hairy legs, I look over into the doorway of the adjoining room, where his ravishingly beautiful wife is being pampered by make-up artists. Sure, beautiful women may be married to goofy guys, but Judd Apatow is smart enough to know that it’s still really funny, even as he insists that it’s perfectly normal.

Knocked Up opens on Friday, Superbad on September 14

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