Saying his "mythic, perfect story" was "one big lie," Lance Armstrong admitted that he cheated during most of his famed cycling career and that he bullied people who dared to tell the truth about it.
After denying doping allegations for more than a decade, he also said he used banned drugs or blood transfusions during all seven of his victories in the Tour de France.
"I will spend the rest of my life trying to earn back trust and apologize to people," Armstrong told talk-show host Oprah Winfrey in an interview that aired Thursday night.
LANCE: "I was trying to win at all costs"
Armstrong, 41, said he started taking performance-enhancing drugs in the mid-1990s and that his "cocktail" of choice was banned testosterone, EPO and blood transfusions using his own boosted blood.
He disputed that he doped during his comeback in 2009 and 2010, saying the last time he "crossed the line" with banned substances was in 2005, his last victory in the Tour de France.
But he still said his comeback in 2009 might have doomed him because it gave anti-doping officials a chance to build the case against him. He said the comeback "didn't sit well" with teammate Floyd Landis, who accused Armstrong of doping in 2010.
"We wouldn't be sitting here if I didn't come back," he said.
Instead of telling the truth about his cheating, Armstrong said he kept covering it up because he got swept up in the "momentum" of his own legend. He was the cancer survivor turned superhero, the squeaky clean rider waving the American flag in victory.
"It just gets going, and I lost myself in all that," Armstrong said.
He also said he didn't think he could compete if he didn't turn to doping because doping was so pervasive in cycling. "I didn't invent the culture, but I didn't try to stop the culture," Armstrong said.
The 90-minute broadcast was taped Monday in Austin, Texas, Armstrong's hometown. A second portion of the interview will air Friday night.
It marked the cyclist's first extended public comments since the U.S. Anti-Doping Agency released more than 1,000 pages of doping evidence against him October. The evidence included sworn statements from former teammates and friends who detailed how and when he used performance-enhancing drugs.
Armstrong said he rationalized his use of testosterone because one of his testicles was removed in his fight against cancer. "I thought, 'Surely, I'm running low (on testosterone),'" Armstrong said.
He also admitted to mistreating people as he tried to preserve the cover-up.
"Yeah, I was a bully," Armstrong said.
Not only did he attack those who told the truth about him, he sued them when they did. At one point, when Winfrey asked him if he had sued Emma O'Reilly, a former team masseuse who told of his doping, Armstrong wasn't sure. "To be honest, Oprah, we sued so many people," he said.
He called his behavior "inexcusable" and described himself as "a guy who expected to get whatever he wanted and to control every outcome."
To make amends, he said he has reached out to those he attacked for telling the truth about him, including O'Reilly and Betsy Andreu, the wife of former cyclist Frankie Andreu. He said he spoke with both Andreus in a 40-minute phone call recently but did not make peace with them.
"No, because they've been hurt too badly," Armstrong said.
He denied pressuring other cyclists into doping, contrary to their testimony in the USADA case. But he acknowledged he has a credibility problem after defiantly lying about his doping for so long.
"I'm not the most believable guy in the world right now. I understand."
He even said he thought he could get away with it last year after the federal government dropped a criminal investigation into whether he committed fraud through his doping scheme. The case was dropped without explanation.
"I thought I was out of the woods," Armstrong said.
But USADA continued to investigate and offered him the opportunity to cooperate. In response, Armstrong said he could not resist his tendency to defend his turf, no matter what. He turned USADA down and fought back, suing the agency in an effort to challenge its jurisdiction - a lawsuit that eventually was thrown out of court.
"I'd do anything to go back to that day," Armstrong said of the day USADA gave him the opportunity to come clean. "Because I wouldn't fight, I wouldn't sue them."
USADA banned him for life from sanctioned events and stripped him of his seven titles in the Tour de France. By coming clean, Armstrong hopes to reduce that ban and compete again - a goal that will require much more than talking to Oprah. Anti-doping officials have made clear that he will have to cough up more details under oath.
After the broadcast, USADA said in a statement, "Tonight, Lance Armstrong finally acknowledged that his cycling career was built on a powerful combination of doping and deceit. His admission that he doped throughout his career is a small step in the right direction. But if he is sincere in his desire to correct his past mistakes, he will testify under oath about the full extent of his doping activities."
Livestrong, the cancer-fighting charity Armstrong founded 15 years ago, said in a statement it was "disappointed by the news that Lance Armstrong misled people during and after his cycling career, including us."
Armstrong stepped down from Livestrong's board in November, saying he did not want his troubles to reflect on the charity.
The Livestrong statement noted he had apologized to the charity's staff earlier this week, "and we accepted his apology in order to move on and chart a strong, independent course. We look forward to devoting our full energy to our mission of helping people not only fight and survive cancer, but also thrive in life after cancer.
"Even in the wake of our disappointment, we also express our gratitude to Lance as a survivor for the drive, devotion and spirit he brought to serving cancer patients and the entire cancer community."
In a preview of Friday's part two of the interview, Armstrong described the day in October when all of his sponsors dropped him after USADA's evidence was released to the public. Referring to his loss in income, he called it a "$75 million day."
On his mother's reaction to his admission, he said, "She's a wreck."
"This is too late," Armstrong said of his confession. "It's too late for probably most people, and that's my fault."