Thursday night, the former House speaker told ABC News that he was "going to be the nominee."
"It’s very hard not to look at the recent polls and think that the odds are very high I’m going to be the nominee," he said.
Romney said that Gingrich was counting his chickens before they hatched.
"Over the last year there've been a lot of people who've been real high in the polls that are not high in the polls anymore," he told the gang on "Fox & Friends." "There's this funny thing in America. It's called an election. You have to win the election. And to win the election, you've got to earn it."
"Self-aggrandizing statements about polls are not going to win elections," he said.
Romney said Gingrich does not have the right background to be the nominee and to lead the country because of his years as a Washington "insider."
"This is not a matter that America needs better lobbyists or better deal-makers, better insiders. I think America needs a leader," he said. "I actually believe that what we need is someone that has lived out in America, not in Washington. Who's had the experience of leading enterprises. Who's led a state, led the Olympics. [Who] by virtue of those leadership experiences, having run things, understands the power of leadership. I do."
After long keeping their attacks focused on President Obama, Romney and his campaign have zeroed in on Gingrich as their chief threat with just a month before the first nominating caucuses.
Romney, though, has been under increased scrutiny himself. In an interview with Fox's Bret Baier on Wednesday, he was asked to respond to attacks both from Republicans and Democrats about his policy reversals on issues like abortion, climate change and immigration.
Romney snapped back, calling it an "unusual interview." Baier later said that after the cameras stopped rolling, Romney made it clear he was very unhappy with the line of questioning, and the aggressive nature of it.
Asked about it Friday, Romney said he thought it was, "all in all," a good exchange.
"I just wanted to spend more time talking about the big issues of the day. It turned out to be a pretty good chance for me to talk about some of the attacks that are coming from the Democrats. So all in all I thought it was a pretty good opportunity," he said. Watch the latest video at video.foxnews.com