"I have to come to a conviction, just like these candidates come to a conviction to run for president, I need to come to a conviction to get fully behind a single candidate, so that's what's holding me back. I hope to get there," said King on CBS's "Face the Nation.”
The Iowa congressman told CBS that he is looking for a nominee that will be able to convince the American people to accept the necessary measures needed to restore economic prosperity and reduce the country's debt.
The Iowa caucuses, which take place Jan. 3, is the first contest to be held in the Republican race.
When pressed on the viability of frontrunner Newt Gingrich's candidacy, King said the former speaker has the best understanding of policy issues of any candidate, but raised concerns about his unpredictability and discipline.
"He is clearly hands-down the one who's got the most breadth, the most depth and the most understanding of policies and the most solutions to put forward, but it's risky to go forward in the fashion that he has and when you're blazing a trail when you're on top of the polls that tends to be a high liability,'" King said.
King, who serves with GOP contender Rep. Michele Bachmann (Minn.) in the House, said he is not ready to endorse her for president despite his agreement with many of her conservative policy positions, including the repeal of 'ObamaCare' and the Dodd-Frank financial reform.
"I haven't come to the conviction, so that's what holds me back," King said.
King also weighed-in on former Massachusetts Gov. Mitt Romney's candidacy, saying he's a better candidate than four years ago.
"Sometimes it's just an intangible and I don't know that Iowans have warmed up to him in the fashion one would think given his positions on the issues," King said.