Rather, Sharpton said he was contrasting himself with Christopher Hitchens, the atheist author he was debating at the time.
"As for the one Mormon running for office, those who really believe in God will defeat him anyways, so don't worry about that; that's a temporary situation," Sharpton said Monday during a debate with Hitchens at the New York Public Library's beaux-arts headquarters.
The comment was first reported Tuesday in a blog on The New York Times' Web site.
The Romney campaign, which has been wary of campaign trail criticism of Romney's faith, jumped on the Sharpton comment. If elected, Romney would be the first Mormon to serve as president.
"It is terribly disheartening and disappointing to hear Rev. Sharpton offer such appalling comments about a fellow American's faith," said Romney spokesman Kevin Madden. "America is a nation of many faiths and common values, and bigotry toward anyone because of their beliefs is unacceptable."
Romney himself said Monday during an appearance on Fox News program "Hannity and Colmes": "I think there are differences between different faiths in this country. And there will be battles between different religions. ... That's a great thing about this country. We don't decide who's going to be in office based on what church they go to."
In a tape of the debate, Sharpton can be heard defending the role of religion in the civil rights movement and shunning any suggestion that there wasn't a religious underpinning to the efforts of its leader, the Rev. Martin Luther King Jr.
Then Sharpton spoke of Romney, although a tape reviewed by The Associated Press does not reveal why.
In a later interview with the AP, Sharpton denied questioning Romney's belief in God and suggested the Romney camp was trying to stir up a controversy because of their political differences.
"What I said was that we would defeat him, meaning as a Republican," Sharpton said. "A Mormon, by definition, believes in God. They don't believe in God the way I do, but by definition, they believe in God."
He said he was contrasting himself and other believers with Hitchens, who is the author of a new book, "God Is Not Great."
Sharpton led the calls for Imus' ouster last month after the talk show host referred to members of the Rutgers University women's basketball team as "nappy-headed hos."