In 1971, actor Dennis Dugan invited filmmaker Roger Corman to his off-Broadway performance of “The House Of Blue Leaves.” Surprisingly, Corman came, and the ensuing talks inspired Dugan to shift from acting to directing.

Cut to 40 years later, when Dugan and Corman are dining as peers the night Dugan learns that his films, including the recent “Grown Ups,” have surpassed the billion-dollar earning mark.

Yet few moviegoers talk about seeing a “Dennis Dugan film” the way they’d name-check, say, Judd Apatow. Nevertheless Dugan has established quite a quiet career as a trusted collaborator with Happy Madison Prods., and a man capable of unleashing the funny potential of today’s biggest box office draws.

“Dennis understands Adam Sandler and he understands comedy,” says Columbia Pictures senior VP Sam Dickerman, who has worked with Dugan on several movies. “Dennis has the great ability to work with the other people, too. He has a remarkable talent to tee up the situation and allow the performers to perform and, in doing so, get the results he needs to make the movie work.”

Take “Grown Ups,” the ensemble film that grossed $162 million domestically with an additional $108 million overseas. Dugan found himself wrangling a cast consisting of Sandler, Kevin James, Chris Rock, David Spade and Rob Schneider. Rather than over-direct the comics, Dugan set out five folding chairs in front of a cabin, sat the actors down and had them riff for two 45-minute takes, steering the conversation only when necessary.

“I try to make the atmosphere chaotic and professional at the same time,” Dugan says. “Funny has one goal: to make you laugh. Part of the thrill and adrenaline comics have is the free fall — am I gonna land on my feet or am I gonna die? If I can make them feel like it’s OK to jump, I get the best out of them.”

It helps that Dugan has that actor’s background. He followed up theater work in New York and Los Angeles with performances in “The Rockford Files,” “Richie Brockelman, Private Eye” and as the memorable Capt. Freedom on Steven Bochco’s seminal “Hill Street Blues.” (Bochco and Mark Tinker would later work with Dugan as a director.)

“Dennis always impressed me as being a genuinely multitalented guy,” says Bochco. “He was a wonderful actor. He was a gifted artist and still is — he did all kinds of interesting, mixed-media things. Just hugely imaginative.”

When Dugan auditioned for the 1988 series “Moonlighting,” creator Glenn Gordon Caron called Dugan to say, “That was by far the best audition,” Dugan recalls. He eventually lost out to Bruce Willis, but was later brought on to play Cybill Shepherd’s new love interest.

Fans revolted, and Dugan was written out — but he was offered the chance to direct a few episodes.

“?’Moonlighting’ got me in the place I had to be for comedy — where there are no rules, just chaos,” Dugan says.

The next step was a challenge.

“At the time there wasn’t a lot of crossover,” he recalls. “You were either a TV director or a film director.”

To get his first feature directing job on “Problem Child,” Dugan demonstrated his creative vision for the film by hopping onto the coffee table of a Universal executive (page A18). This marked the second time Dugan worked with Ron Howard and Brian Grazer’s Imagine — the first being his role as an actor in 1989’s “Parenthood.”

“Brain Donors” followed, and Dugan fought to cast the then little-known Sandler. Though he lost, Sandler remembered the persistence, and when Dugan came in to pitch himself on “Happy Gilmore,” Sandler immediately deemed him the man for the job.

The friendship and professional relationship blossomed; Dugan has five Sandler films under his belt (plus one with Sandler as a producer), and two more coming out in 2011.

“I think I make his life easier: He’s the hardest working man in show business, and he needs comrades to take the pressure off him,” Dugan says, adding that Sandler makes his life easier, too. “I’m not out reading scripts all the time, out on the market. But there’s no slacking off. I feel if I’m not out there kicking ass every day, they’ll find someone else who is.”

Gary Martin, head of production at Sony, has worked with Dugan on nine films, plus next year’s “Jack & Jill” and “Just Go With It.” He’s attracted to Dugan because his work is embraced by people — and for his professionalism.

“If there are any issues, he’s always willing to work with the studio,” Martin says.

When asked about Dugan’s artistic style, Martin hedges and reiterates Dugan’s work as an actor prior to directing. Perhaps its tough to nail down Dugan’s style because his focus begins and ends with the talent.

He’s a chameleon, adjusting his expectations to fit the needs of the cast and the script. And he’s become so adept at this process, his output is starting to look as prolific as Corman’s.

“It’s like I was a really good ballplayer up through high school, then when I got to the pros, I realized I was a good utility ballplayer,” Dugan says. “While I’m funny, when I saw really, really funny guys, I realized my greatest contribution to film comedy is to be a comic enabler. I can stoke the first of those guys. And they can trust me.”

More articles from Billion-Dollar Filmmaker: Dennis Dugan:
Quiet hitmaker | Duo defies critics | In the pipeline | Dugan scores with sports | At work with Dugan | Filmmaker recalls favorite moment