In the fall of 2008, Alex Gibney rolled up in a rental car to the imposing metal gates in front of Lance Armstrong's home in Austin, Texas, rang the buzzer, and announced himself to the intercom. Incredibly, the gates swung right open to one of the last people you'd think Armstrong would want nosing around at the time.

By then Gibney had already sealed his reputation as a special brand of filmmaker – the crusading muckraker. Earlier that year, he'd won an Oscar for 'Taxi to the Dark Side,' which chronicled the story of an innocent Afghan taxi driver who died after being beaten by American soldiers at Bagram Airfield. And in 2005, his 'Enron: The Smartest Guys in the Room' laid out a devastating summation of the financial crimes of Enron's executives.

Gibney's playbook should not have been a mystery to anyone with a Netflix account and a few hours to kill: exposing the villainy of those who for too long had been allowed to abuse their power. And here he was driving onto the $10 million estate of a guy who had been keeping a huge, not particularly well-hidden secret for more than a decade through personal intimidation, lawsuits, and brazen public relations. "Part of what he was doing," Gibney says, speculating on Armstrong's cooperation, "was showing everybody: Look, clean or dirty, I can beat anybody. Gibney does investigative films, so take a look in the cupboards, look in the closets, see if you can find anything."

Inside the gates, it became clear just how much was riding on this gambit. There was a Mediterranean cabana overlooking the pool, rows of cypress trees, and an 8,000-square-foot house designed by the architect who also did Armstrong's homes in Spain, New York, and the Bahamas, and his Texas ranch. A few miles away, Livestrong, the cancer charity Armstrong founded, was building sleek new headquarters to house its 70 employees, who hoped to build on the $300 million they'd already raised based on a version of the cyclist's story that didn't include steroids, EPO, or illegal blood transfusions.

Armstrong met Gibney in shorts and a T-shirt, and without his usual handlers. Gibney told the cyclist he wanted to trail him during his 2009 Tour de France comeback because he was fascinated by his will – to come back from cancer and win his first tour, to win six more, and then to now attempt to win another. Gibney didn't come on like a superfan; he told his subject that ignorance had never stopped him before. "I'm a good learner," he told Armstrong. "I can dig in. I knew nothing about mark-to-market accounting when I started the Enron film."

Unless Lance Armstrong marries Miley Cyrus, or launches a second career as a televangelist, Gibney's new film, 'The Armstrong Lie,' will be among the definitive documents of his career. Like other Gibney films, it's dispassionate and fair in the presentation of information but ultimately devastating about its subject. 'The Armstrong Lie' doesn't break much news, but in it Gibney assembles a case so exhaustive and damning that anyone who sees the cyclist as merely a liar will be forced to reclassify him as a sociopath. The ease with which Armstrong eviscerated anyone who challenged his lies – Greg LeMond was a drunk, masseuse Emma O'Reilly was a slut, investigative journalist Paul Kimmage hated cancer survivors – is undeniably chilling.

Armstrong could not have made his life more open to Gibney during the 2009 Tour – he allowed his daughters to be filmed and even encouraged Gibney to be there for his drug tests. At times, the director can be heard laughing with Armstrong like a chummy cohort, cheering him on during the Tour. "When you're hanging out with Lance, he's a good guy," Gibney says. "On a day-to-day basis, I like him! What's not to like?" But ultimately, no amount of camaraderie would distract Alex Gibney from making an Alex Gibney film.

Staging your own Gibney film festival can be emotionally draining. You find yourself toggling between anger and profound depression about how inexorably fucked-up the country is. Gibney knows his films can be demoralizing: "They are depressing because the system's rigged, and it's very hard to figure out how to unrig it. You know money rules. And it relates to the Armstrong movie, too – there is a view in our country that winning at all costs is okay. Fuck people on your way to the top. It's okay as long as you get to the top. Nobody likes a loser."

In the past few years, the 60-year-old Gibney has focused much of his indignation on what he sees as noble cause corruption, a police term that means that cops can forgive themselves pretty much any behavior if in the end the bad guys go to jail. "People who lie, particularly those who lie really big, can't do it effectively unless they feel that there's a righteous power behind what they're doing," Gibney says. "You're entitled to lie because the end justifies the means. Think of all the money you're raising for cancer. You wouldn't be able to do that if you were busted for doping, right? Lance can feel . . . righteous. To me, that's where it gets fucked-up."

The 17th-floor offices of Jigsaw Films, on West 26th Street in Manhattan, are a hive of activity. On a late September afternoon, there are about 15 people working in the office, two editing bays, and a young guy who looks a little alarmed when he realizes that his efforts to pull a salad from the fridge are blocking Gibney's path. Gibney's overall affect is stern and imposing – he looks a bit like Vladimir Lenin – but then he'll laugh, revealing a gap-toothed smile, and he suddenly seems about as menacing as Alfred E. Newman. In his office overlooking the Hudson River hangs a brutal 2010 review of his movie about the downfall of New York governor Eliot Spitzer, 'Client 9,' from Kyle Smith of the 'New York Post.' "I wonder how Gibney operated the camera while on his back," Gibney reads aloud, and howls with laughter.

While contemporaries like Errol Morris might take five years between features, Gibney will sometimes complete more than two a year. In 2010, he did 'Client 9,' as well as 'Casino Jack and the United States of Money,' about disgraced lobbyist Jack Abramoff. He also released a film version of Lawrence Wright's play 'My Trip to Al-Qaeda,' and still found time to contribute a segment to a film based on the best-selling book 'Freakonomics.'

He laughs when I ask him if he's the first documentary filmmaker to get rich. "I wouldn't say rich, but I can make a living," he says. "It's hard to make a living doing documentaries. Frankly, if it takes you five years to do a film, and that's the only film you're doing, you're in trouble."

In many ways Gibney has industrialized the documentary world, a multitasker in an industry known for single-focus auteurs. He gives his editors great leeway to imprint the films with their own personal vision, like his longtime editor, Alison Ellwood, who directed Showtime's Gibney-produced rockumentary 'History of the Eagles.' And he is not averse to using the reporting and footage of others as building blocks for his own films. 'Enron: The Smartest Guys in the Room' relied heavily upon the Rolodexes of the two 'Fortune' reporters who had written the book upon which the film was based. 'We Steal Secrets,' his WikiLeaks film, was defined by footage of Assange shot by Australian journalist Mark Davis in 2010.

"Alex has turned his company into a bit of a factory," says his onetime collaborator, Eugene Jarecki. "But the big debate is, is factory a bad word? A problem that anyone will face if they make too many things is that by nature, it is hard to control the quality of what you're making. But I think Alex would argue that this world is so ripe with indignities and he wants to get through them as quick as he can."

Whatever his motivation, Gibney likens his outfit to more of a "juggling operation. Like a lawyer, I have a lot of cases, and you never know exactly how the cases are going to work and who you're going to get to talk to you when. I never crank out films in a hurry. I have a bunch of great teams, and I just don't let anything out of the shop until I think it's really good."

Since Gibney found his métier at a fairly advanced age – directing his breakout Enron documentary at 52 – what might look like workaholism could simply be his trying to make up for lost time. Either way, Anne DeBevoise, his wife of 31 years, a yoga instructor in Summit, New Jersey, where they live, sees very little of her husband. Neither does Ella, the youngest of their three kids and the one who still lives at home. "It's an issue," he says.

Over the years, Gibney has earned a reputation for being as hard-charging in making his films as the films are themselves. He battled with director Eugene Jarecki over control of 2002's 'The Trials of Henry Kissinger,' with Gibney complaining that Jarecki tried to outpace him so he could seize creative control. Jarecki counters: "The notion that Alex Gibney could be burned out by anyone would have been like trying to outrun Jesse Owens and being surprised by the results. Alex is a competitive guy. It's a part of what's great about him, and it's also to some extent what he may struggle with."

Even winning an Oscar – for 2007's 'Taxi to the Dark Side' – was laced with acrimony. After it failed, in Gibney's opinion, to capitalize on its Oscar win – it made less than $280,000 in theaters – the director filed for arbitration against ThinkFilm, the movie's distributor. Mark Urman, ThinkFilm's founder, blames the documentary's subject matter, and says he feels betrayed by Gibney's accusation that he left the movie in the lurch. "Crusaders are important, and Alex is a crusader," Urman says. "The world needs them, but you have to be careful when you get in business with a crusader, because what if he decides to crusade against you?"

Those who sign up to participate in a Gibney film can never be sure if in the final cut Gibney will be crusading with them or against them. Not long after a prostitution scandal forced him to resign the governorship of New York in 2008, Eliot Spitzer agreed to sit for Gibney. "I took a calculated risk that he would allow me to express my views and those who disagreed with me could express theirs," Spitzer says. "How he would filter it and put it together, I did not know." Spitzer was rewarded with 'Client 9,' a film that, while not glossing over his black-socked adventures with call girls, makes a compelling case that his fall was choreographed by plutocrats like AIG chairman Hank Greenberg and Home Depot founder Ken Langone, who were embittered about getting ensnared in Spitzer's investigations while he was attorney general.

Unlike Spitzer and his movie, Abramoff is not a big fan of 'Casino Jack and the United States of Money,' a film that crucifies him in every way imaginable – as a bilker of Indian tribes, whose money he happily hoovered while privately referring to them in emails as "troglodytes," and, suspiciously, as a primary beneficiary of a gangland-style murder. "I don't mind being the villain," says Abramoff, who says he would have talked to Gibney had cameras been allowed in prison. "But the film was a wasted opportunity. He could have used my case to highlight corruption that's systemic, but instead he went off on this tangent with me. It was filled with ideological attack and personal opprobrium. He primarily focused on the right."

Gibney doesn't see himself as a predictable leftist, citing the hysterics his WikiLeaks film caused among liberals because it was highly critical of Julian Assange, particularly in the way he dealt with the accusations of rape by two Swedish women. "Just because I admire the idea of WikiLeaks doesn't mean that I support Julian's assassination of two women," he says. "Why did I have to sign up for that?" His sensibility, he says, transcends politics. "I think of my films as not necessarily political but more moral," he says. "Between my father, my stepfather, and my mother – they all felt pretty passionately about the importance of standing up and doing the right thing, and none of them were suck-ups. What motivates me is usually abuse of power."

Gibney grew up in Cambridge, Massachusetts, with his mother, Harriet, a divorced writer who was education director of Children's Hospital. His father, Frank, was a journalist and one of the country's foremost experts on Japan, who rose most mornings at 4 to write, and churned out nearly a dozen books as a result. It was a quality his son came to admire at a young age.

Then in 1969, when Alex was 15, the family moved to New Haven, Connecticut, after Harriet married William Sloane Coffin, a Presbyterian minister whom she'd had an affair with early in her marriage to Alex's father. Coffin's job – as chaplain of Yale – doesn't do justice to his superstardom at the time. From Yale's pulpit, he championed every liberal cause of the day – civil rights, opposition to the war in Vietnam, nuclear disarmament, gay rights. 'The Nation' called him "the clear heir to Rev. Martin Luther King." Watching his father and stepfather, Gibney learned firsthand what real competition looked like. Coffin and Frank Gibney died within days of each other in 2006, and their obits appeared on the same page of 'The Washington Post.' Only Coffin's appeared in that day's 'New York Times.' Gibney says: "If I believed in the afterlife, I'd say somewhere smoke was coming out my father's ears."

Life with Harriet and her celebrated new husband wasn't easy. "There was a lot of tension because Bill was such a larger-than-life figure," Gibney says. "She was a volatile character, and he was also volatile, but he overshadowed her." The fact that they were both alcoholics didn't help. "My mom could be brutal when she was drunk," he says. In what became a tabloid headline of the day, in their 1979 divorce proceedings Harriet testified that during one fight, the famous pacifist had delivered a karate chop, which resulted in Harriet's suffering a hairline skull fracture. This was unsurprising to many who knew them socially. "We all wanted to hit her," one of Coffin's best friends told his biographer.

Luckily, Tiger, as Alex was known then, was spared a lot of this, first shipping off to prep school in Connecticut, and then following in the footsteps of both his father and his stepfather and enrolling in Yale. He wasn't particularly engaged in politics on campus. "We were sort of alienated, actually," says his friend and classmate Peter Bull, who lived for two years with Gibney in his parents' house while they were on sabbatical. "There's an elite pomposity that goes on in the Ivy League, and it rubbed both of us the wrong way."

Given his stepfather's prominence on campus, it's easy to understand why Gibney headed in a different direction. "I was politically interested, but I wasn't politically active," he says. "To some extent I was wanting to go my own way and do my own thing. And organizations have always freaked me out." At Yale, he studied Japanese language and literature, like his father. His dad hoped he'd join 'Time' or 'Newsweek' after college. "Halfway through, I got tired of spending my time in the character dictionary," he says. "So I jumped ship and started to get interested in film."

To his family's great befuddlement, after graduating, he enrolled in UCLA film school and later dropped out when he was offered a job at the Samuel Goldwyn Company, which proudly distributed art-house fare from around the world and, less proudly, homegrown exploitation films. As "director of special projects," a title he invented, Gibney would cut trailers, recut foreign films, and occasionally lend his voice to dubbing. He worked on movies such as 'Shock Waves' ("All about Nazis that come up from the bottom of the ocean floor") and 'Invasion of the Bee Girls' ("They fuck guys and then they die"). Apparently, the stuff you pick up cutting jiggle films can be applied to more edifying topics. With his father's help, Gibney was hired to write and produce a 1992 PBS miniseries based upon Frank's work, called 'The Pacific Century.' "That was a huge break for me," Gibney says. "Suddenly I had a shot, and luckily I didn't fuck it up."

His success on the Asia series led him to producing high-profile series such as David Halberstam's multipart PBS documentary on the 1950s, and another about sex. But it would take another decade, when he was in his forties, for his biggest break to come along, when Martin Scorsese hired him to produce his seven-part PBS series 'The Blues,' which aired in 2003. Besides flinging open countless doors, the project gave him a front-row seat to watch directors like Scorsese, Clint Eastwood, and Wim Wenders working on their segments in a nonfiction style that tossed out the musty old PBS documentary. "Wim's film starts in outer space," he says. "I saw that anything is possible."

'The Armstrong Lie' is not the movie producer Frank Marshall set out to make. His vision, 13 years ago, was for a Hollywood biopic on Armstrong culminating in a Rocky-esque triumph. Marshall is well-known in Hollywood, producing franchises like 'Indiana Jones,' 'Back to the Future,' and later, the 'Bourne' movies. But he's also a jock. In 1992, he got himself a slot on the U.S. Olympics Committee, where he formed a close relationship with Bill Stapleton, a former Olympic swimmer who was also Lance Armstrong's lawyer, agent, and right hand. In 2000, Stapleton showed Marshall galleys of Armstrong's memoir, 'It's Not About the Bike,' which chronicles Armstrong's road from his 1996 cancer diagnosis to winning the Tour de France three years later. "It's a movie," Marshall told him, and immediately optioned it.

Marshall showed up at Sony with his 'Bourne' star, Matt Damon, who wanted to play Armstrong, and sold the project that day. Hollywood being Hollywood, the film never happened. By 2008, the project seemed all but dead: Armstrong was in full retirement mode, saying he was done with the bike forever, and leading journalists to believe he was mulling a run for Texas governor in 2010. That summer, as he watched Spanish rider Carlos Sastre pokily win the 2008 Tour de France, Armstrong changed his mind about retirement. "I'll kick their asses," he said, and announced that he'd vie for an eighth jersey in 2009.

Marshall's Armstrong movie was back on, but now as a comeback documentary, which Marshall hoped would pave the way to finally making his biopic after Armstrong was truly retired. By then Marshall and Armstrong had formed a bona fide friendship; Marshall was with Armstrong when he won Tours in 2002, 2004, and 2005. Marshall and his partner on the project, Matt Tolmach, decided that Gibney, who had just won his Oscar, should direct. The producers sent him off to Austin to meet their star, who voiced no objections. And they were off.

At that point, Gibney was convinced that despite the evidence of Armstrong's past doping, he was making a special point of riding clean in 2009. "Look, as you get older you root for the old guy who comes out and tries to beat the young guys," Gibney says. "And it seemed like he was doing it clean, right? So I thought, 'This is his redemption story.'"

Immediately, Gibney was stunned by the openness of the Armstrong camp, which had a reputation for being fiercely protective. To his great shock, Stapleton even helped Gibney secure an interview with Armstrong's former doctor, Michele Ferrari, with whom Armstrong had had to cut ties in 2004 when he was convicted in a lawsuit that revealed him to be the most sophisticated doper in the cycling world. "That was a jaw-dropper," says Gibney of landing the elusive Ferrari.

The one big issue that Armstrong and his team had was that Gibney had hired as a technical consultant Kent Gordis. Gordis, a sports TV producer, had co-written a book with three-time Tour winner Greg LeMond, Armstrong's archenemy and one of the first people to publicly suggest Armstrong was doping. "Lance's team tried to get him tossed, but I kind of dug my heels in," says Gibney. "I didn't feel it was appropriate for Lance's peeps to be telling me who I could hire."

Even then, back in 2008, Armstrong's team knew that doping allegations would be addressed in the film. The only thing they requested was that Armstrong be given the opportunity to respond to any charges made in the film, a skill at which he'd become particularly adept.

But nobody, not even his own producers, knew what Gibney would do with the film after the 2009 Tour. Weeks after returning from France – where Armstrong came in third – Gibney was on a plane to Michigan to persuade Betsy Andreu to help on his film. Andreu was married to Frankie Andreu, a 1999 Postal Service teammate. The couple's 2005 testimony about Armstrong's doping, followed by Armstrong's seeming attempts to destroy them, had put the Andreuses at the center of those trying to expose Armstrong. Initially, they were wary of Gibney, assuming that any film Armstrong's buddy Marshall would make would be a puff piece. So Gibney flew Kent Gordis to meet them in Michigan, where he vouched for Gibney as no Armstrong hagiographer.

Had Marshall known who Gibney was interviewing, he would not have been pleased. Even in light of all the damning circumstantial evidence, as late as 2010 Marshall still believed that his friend was not a doper. "I always thought, 'If everybody's getting busted, why isn't Lance?'" says Marshall. So in 2010, when Gibney finally delivered a cut of his film to Marshall and Tolmach, they were shocked and unhappy when they saw how deeply Gibney had delved into the doping. "I thought this was a movie about a comeback," Marshall says, "not about doping." The two producers were soon screaming at their wayward director inside a tight cutting room on the Sony lot.

But then, it was all moot. Just before Gibney finished his cut, Floyd Landis dropped the dime on Armstrong on 'Nightline,' rendering the film all but irrelevant. Following the October 2012 release of the United States Anti-Doping Agency's damning report, Armstrong invited Marshall and Tolmach to his house and finally admitted the truth and said he would soon talk about it publicly. "I felt devastated and betrayed," says Marshall.

In order to salvage the film, Gibney sat down with Armstrong in January of this year, three hours after his Oprah interview. Gibney taped a few more interviews with Armstrong's critics, then started recutting the film, his way, and with the full support of the producers. Armstrong's personal feelings about the film were no longer a concern to Marshall.

Gibney adamantly denies that he signed up for the project secretly hoping he'd be present for Armstrong's unraveling. Marshall isn't so sure. "I know that nothing would have made Alex happier than to have been present for a positive drug test," says Marshall wearily. "I'm telling you, I'm sure Alex was just waiting for this to happen."

When the unraveling did happen, Gibney does admit he celebrated the fact that his movie had just gotten a whole lot more interesting. "Part of me did think that, of course," he says. Gibney concedes that his film delivers a huge beating to Armstrong. "I did wallop him in the end," he says. "And I think that was justified. He also walloped himself. I mean, I think my films try to be sympathetic. But you can be sympathetic and then still render a judgment."

The million-dollar question is why Armstrong ever let Gibney near him in the first place. "It makes me think that some part of him wanted somebody to figure it all out," says Tolmach. "How can you not think that? For someone as controlled as Lance Armstrong, it's too reckless an idea." In May, Gibney sent Armstrong an email breaking the news about what he was calling the film. "I don't know whether to be more angry about the title," Armstrong wrote back, "or the fact that you still can't spell peloton."

Gibney has never viewed Armstrong as a simple villain. "People like to compare him to Bernie Madoff," he says. "I don't think he was like Bernie Madoff. I think he was a fucking awesome athlete. He's athletically talented, works really hard, and has a kind of killer instinct. Sometimes that is what separates the men from the boys. We admire that on the bike. It's not so pretty off the bike."