"It had nothing to do with me," he told Winfrey. "As I say, there is always someone waiting in the wings in this business to take your job. If you're not doing the numbers, you move on, it's that simple."
Leno also revealed that he still hasn't spoken to his former colleague.
"It didn't seem appropriate," he told Winfrey. "I don't know, let things cool down, I think we'll talk."
Remorse barely bled into Leno's musings about the ugly affair. He painted himself as a victim of TV wheeling and dealing, saying he never wanted to relinquish the show to O'Brien but was informed by the network in 2004 that O'Brien would take over in 2009.
"I was devastated," he told Winfrey. "But you know something? I was happy with what I had. ... I was going to do my best to keep it No. 1 for the next five years."
Leno admitted he was lying when he told his audience, at the close of his "Tonight Show" reign, that he would leave TV.
"I did tell a white lie on the air and said I was going to retire," he said. "I found it easier that way."
Leno said he always wanted to continue his career in showbiz. While he could've left NBC, he contended, "going to another network, boy it's a lot of work."
So he accepted NBC's offer to give him a 10 p.m. show, though he hinted that he knew "The Jay Leno Show" was destined to fail.
"You're going into uncharted territory; it's a lot more competitive," he told Winfrey. "To try and book against the 'CSI' evil twin episode, that was going to be very hard."
Asked why he thinks "The Jay Leno Show" tanked, the host's answer was simple: "It was basically a late night talk show at 10 o'clock."
He also argued that other networks refused to let their talent guest on his show because it competed with their primetime lineups.
"The unusual thing was that they actually boycotted us," Leno said. "It was a calculated effort to keep their guests off our show. [It made things] more difficult."
Leno himself became the butt of late night comics' jokes in the wake of NBC's announcement that it would take away the 11:35 p.m. time slot from O'Brien. Winfrey asked him if the widespread bashing, from Hollywood and beyond, hurt.
"It's like being a fighter and saying, 'You got punched in the head, did it hurt?' Well, yeah, but you're a fighter," Leno contended.
Now, on the verge of reclaiming "The Tonight Show" after NBC airs the Winter Olympics, Leno's not so sure he can make the show No. 1 again.
"I don't know," he said. "You work hard and you try, and it's sort of a marathon; you do the best you can."