His latest documentary,is being released in theaters nationwide this week, and it has just won the top prize at the Cannes Film Festival.
As Correspondent Bob Simon reported last summer, Moore's last film, "Bowling for Columbine," won the Oscar for best documentary in 2003.
"Bowling for Columbine" poses a question: Why do so many Americans kill each other with guns?
It opens with Moore visiting a bank that gives you a gun instead of a toaster as a premium when you open an account.
"Bowling for Columbine" is, in part, a love story: America's love affair with guns.
"How many people are killed by guns each year? In France...255. In Canada...165. In the United Kingdom...68. In Australia...65. In the United States...11,127," says Moore in his documentary.
But is the problem the number of guns in America? Moore thought so, until he went to Canada, and found they've got lots of guns, too. But, for some reason, they don't lock their doors.
So what is it that makes Americans shoot each other so often? Moore ties America's penchant for gun violence to fear - our fear of each other and of the world.
"I think we have, like, a shared mental illness. A collective mental illness, when it comes to how we view the world. And we're afraid of the other, you know, the people that are out there," says Moore.
The fact that Americans are afraid of the rest of the world may have seemed totally irrational up until 9/11. But it doesn't seem quite so irrational anymore.
Moore, however, disagrees: "Three-thousand Americans were killed. There's 290 million Americans. All right? The chance of any of us dying in a terrorist incident is very, very, very small."
"You've got the Bush Administration using that event in such a disrespectful and immoral way," he adds. "Using the deaths of those people to try and shred our civil liberties, change our Constitution, round people up. That's not how you honor them, by using them to change our way of life as a free country."
While President Bush was enjoying 70 percent approval ratings, Moore's blistering satire of the Bush Administration, "Stupid White Men," was topping bestseller lists all over the country.
But remarkably, it almost never made it into the bookstores. It was due to go out on Sept. 11, 2001, and the publisher was reluctant to release it.
"They said, 'Mike, America has changed. And we can't put out a book called 'Stupid White Men,' not these days. So we would like you to rewrite up to 50 percent of the book, take out all these references about Bush. You know, we don't want you to change your mind about Bush, just tone it down. It's a new day in America,'" recalls Moore.
When Moore refused to rewrite his book, Harper Collins refused to release it. Moore was out in the cold and with nothing to lose, so he decided to read a few chapters to a small audience in New Jersey. There was a librarian in the back of the room.
"She goes home, gets on the Internet, right? Goes into these librarian chat rooms, or whatever. I mean, I had no idea librarians are meeting in chat rooms," says Moore.
"But she tells these librarians they're gonna ban Michael Moore's book. And I get a call a couple of days later from Harper Collins. 'We're getting hate mail from librarians.' I said, 'Whoa! That's one terrorist group you don't wanna mess with. Oh, librarians! Whoo! Scary stuff.'"
In fact, librarians do have fearsome powers in the book industry, and Harper Collins released the book. The rest, as they say, is history.
It's hard to believe that this angry not-so-young man had a very happy childhood growing up in suburban Michigan in the '50s. Moore went to Catholic school, decided to become a priest, and then thought again.
His anger first surfaced in his hometown, Flint, Mich., a General Motors company town that closed down many of its plants in the '80s and moved them to Mexico.
The dream world of Moore's childhood turned into a nightmare of unemployment and desolation, and he started a radical newspaper to challenge GM. But it wasn't enough.
"I decided after a certain point, after writing about this for so many years, I'm thinking, 'I'm not getting anywhere writing about it. What else can I do? Well, let's see. I like going to the movies. Maybe I should make a movie,'" says Moore.
And that's what he did, even though he had no previous filmmaking experience and no money. Undaunted, he sold everything he had, went into debt, and made "Roger & Me," a searing indictment of GM and its chairman Roger Smith, who ordered those layoffs despite posting record profits.
In the film, Moore vainly pursues Smith at a country fair, at Smith's athletic club, and at GM's headquarters in Detroit.
"Of course, I was having a hard time finding my business card since I don't have any business cards, so I gave him my discount pass to Chuck E. Cheese. But he said that wouldn't get me in to see Mr. Smith," says Moore.
At the end, Moore finally succeeds in having a word with Roger Smith, but only a few words:
Michael Moore: Can you come up to Flint with us?
Roger Smith: No, I can't come to Flint, I am sorry.
At the box office, "Roger & Me" was hailed as an instant classic, and the working class hero became a millionaire. He got a couple of his own primetime network TV shows - part 60 Minutes, part "Saturday Night Live."
The centerpiece of "Roger & Me," chasing down the rich and the powerful, now became Moore's signature in his show "The Awful Truth."
He hounded Ken Starr with his own witch-hunt: "Judge Starr, Judge Starr, I think I've found a cheaper way to have a witch-hunt," shouted Moore.
And when an unopposed congressman from New Jersey stood for re-election, Moore registered a house plant, a ficus, to run against him: "Let's face it. Congressman Frelinghuysen doesn't know his ass from a hole in the ground. Vote Ficus. His ass is a hole in the ground."
And in another episode, Moore took up the case of a dying man who had been denied a pancreas transplant by his HMO: "I signed with Humana and all I got was this lousy T-shirt. But no pancreas."
The HMO's PR man kicked Moore out of the building, so Moore held a mock funeral for the dying man outside the company's headquarters. It may have been a stunt, it may have been in questionable taste, but the HMO gave in.
The guy got his pancreas, and is alive and well today.
But, remarkably, despite his success, Moore insists he's really introverted, shy and not cut out to do this kind of work.
"I hate it, actually. I hate doing it. Guys like me from the working class are not supposed to have their own network show," says Moore.
But it is those network shows, and Moore's movies, that have prompted critics to charge that he goes overboard in his pursuit of the powerful, as they say he does in his Academy Award-winning film "Bowling for Columbine," when he confronts the National Rifle Association's president, Charlton Heston.
Heston provocatively held a gun rights rally in Denver shortly after the massacre at Columbine High School, a few miles away. Moore never imagined Heston would speak to him, but he studied the Hollywood star map and decided to give it a shot.
"So I ring the buzzer. And out of that little box came the voice of Moses. 'Yes?' And I'm going, 'Oh my God, What am I gonna do?' And then he told me, come back tomorrow morning, and give me the interview. And he did," says Moore.
Does Moore feel bad about grilling Heston?
"He is the president of the most powerful lobby in Washington, D.C. If he can't hold his own, I don't know, you don't really feel sorry for him," says Moore. "Because what he's up there doing is promoting easy access to as many guns as possible. And that's caused a lot of heartache in this country."
Heston eventually walked out on Moore during the interview, but it was Moore who got pilloried in much of the mainstream media for once again dragging people in front of a camera just to humiliate them.
"I drag people who have made life miserable for millions of people in front of the camera and they humiliate themselves," says Moore.
But are his films really about guns, or General Motors or Flint - or simply Michael Moore?
"I realize I'm there as a stand-in, for all the average, you know, Joes out there who don't get to make a movie to express their point of view, which happens to be similar to mine, so they can sit there in the theater, and give the screen the old Bronx cheer every time we walk into those corporate headquarters, or do something that is for them," says Moore.