Credit: Jason LaVeris/FilmMagic; Ethan Miller/Getty Images

If Levi Johnston could take back anything, it would be... posing for Playgirl? His on-off, on-off relationship and engagement to Bristol Palin, mother of his son Tripp, 20 months?

Nope. For Johnston, his biggest and only regret is a public apology he made to his famous would-be mother-in-law, Sarah Palin.

"I don't really regret anything," Johnston, 20, says in a CBS Early Show interview broadcast Friday morning. "But the only thing I wish I wouldn't have done is to put out that apology [to Palin and the Palin family]."

"'Cause it kind of makes me sound like a liar. And I've never lied about anything. So that's probably the only thing. The rest of the stuff I can live with."

So why did he apologize to Sarah in the first place? "That was something I did to make my fiancée happy," he said. (Johnston and the former Vice Presidential candidate famously traded insults via the press following his early 2009 breakup with Brisol.)

Johnston -- he and Bristol, 19, called off their second engagement last month -- recently signed on for a reality show and is running for mayor of Wasilla, Alaska.

Will he be a better leader than Sarah, Alaska's former governor? "Let's hope so," he says during the interview. "I can't guarantee or promise you anything but I'm gonna try… That's the goal."

"If we do win, I'm going to have to give up Hollywood for three years."