Here are five things Colbert revealed during the interview.
He Has Never Watched His Shocking White House Correspondents Dinner Speech
At the 2006 White House Correspondents Dinner, Colbert delivered a controversial speech that had audience members, especially President George W. Bush, squirming in their seats.
The 24-minute speech, which he delivered in character, was a sarcastic “tribute” to the then-president that poked fun at the president's character and the administration’s policies.
“I stand by this man. I stand by this man, because he stands for things,” Colbert said in his speech. “Not only for things, he stands on things -- things like aircraft carriers and rubble and recently flooded city squares. And that sends a strong message, that no matter what happens to America, she will always rebound -- with the most powerfully staged photo ops in the world."
Colbert told Oprah that he has never watched the much-talked-about speech, which became an Internet sensation.
“No, I have never watched it. I haven't really read the press. I couldn't bring myself to."
He also believes that he “did not cross the line” during the career-defining moment.
Audience Demand Led To 'The Colbert Report'
Before he had legions of fans known as the Colbert Nation, Colbert was a correspondent on “The Daily Show” with Jon Stewart. During the hit political satire series, fake promos for “The Colbert Report,” aired, and audiences called Comedy Central repeatedly to find out when the show would be broadcast.
“I loved working for and with Jon, but we used to say, ‘what a shame that we’re not doing that other form of show,’ because, certainly in cable news, the king shows are pundit personality shows,” said Colbert. “So we started pretending that we had one called ‘The Colbert Report,’ but we just ran commercials for it. We did fake promos for the show that didn’t exist.
“People kept called up and saying, ‘When’s that show going to be on? I want to watch that show.’ So eventually, we said, ‘Why don’t we just do that show?’”
His TV Persona Is Based On Various Newsmen
Colbert told Oprah that the ill-informed news host he portrays on “The Colbert Repot” was mainly inspired by über conservative political commentator Bill O’Reilly. He also said that Anderson Cooper and Geraldo Rivera have influenced the character.
"O'Reilly would be the biggest [influence], because O'Reilly is the king," Colbert said. "O'Reilly has been No. 1 in cable news for 15,000 weeks running or whatever.
"He's Papa Bear, but there are a lot of other people sort of mixed in when we started," Colbert continued. "I wanted to be sort of as shiny and as new as Anderson Cooper, you know as ... the Silver Surfer of cable news, just shiny and kinda sexy.
"Also a little bit of Geraldo Rivera, because Geraldo has a real sense of mission. There's a real sense of Geraldo that every report he does is changing the direction of this great ship we call America.”
Believes Happiness Is Overrated
Colbert, who once categorized “The Colbert Report” as the “joy machine,” told Oprah that he lives by the quote, “Joy is the most infallible sign of the presence of God.”
“Joy can be hard. Joy is not the same thing as happiness,” he said. “I think happiness is overrated. I really do. Happiness can be really facile.”
The funnyman said that he’d rather be “sad with the people [I] love ... because that’s real.”
Suffered A Horrific Family Tragedy
On Sept. 11, 1974, Colbert lost his father, James Colbert, and two older brothers, Paul, 15, and Peter, 15, when Eastern Airlines Flight 212 crashed in Charlotte, N.C. Colbert was 10 years old at the time.
Colbert says that he didn’t begin to process the tragedy until he started college eight years later, causing him to drop 50 pounds.
“I didn’t really feel the loss until I was in college. Then I was in bad shape. I went into college at about 185 pounds. By the end of my freshman year, I was 135. I was just green. I was so sad about it.
“I finally had time to ... be alone with the idea that they were gone.”
The funnyman is currently promoting his newest book, “America Again -- Re-Becoming the Greatness We Never Weren’t,” which hit stores on Tuesday.