DeSantis says Romney 'never fought for us.' An unearthed yearbook photo shows he once campaigned for him

Florida Gov. Ron DeSantis on Tuesday took aim at fellow Republican Mitt Romney, painting the outgoing senator as a member of the "surrender caucus of Republicans" who "never fought for us in the beginning."

"I don't really know Mitt Romney," DeSantis said in response to a question about a Romney-backed gathering of presidential candidates last month.

But a black-and-white photograph from DeSantis' Harvard Law School yearbook unearthed by ABC News indicates that at one point, DeSantis campaigned on Romney's behalf.

The image shows the cheerful-looking law student wielding a "Romney for Governor'' sign during the 2002 Massachusetts gubernatorial campaign -- an election Romney handily won, launching his political career.

A caption on the page describes the school's "Law Republicans" group as the "voice" of the Republican Party at Harvard Law, aiming "to provide a social community of moderate and conservative Republicans." The group would "organize community blood drives and a Ronald Reagan birthday celebration," according to the text.

On Tuesday, DeSantis called Romney one of "the same old, same old Republicans who have never fought for us in the beginning."

A spokesperson for the DeSantis campaign declined to comment to ABC News.

More than two decades separate DeSantis' critical comments from the yearbook photo, and both men have undertaken vastly different trajectories in the intervening years.

Romney emerged as the Republican party's presidential candidate in 2012, but has since become a pariah as the GOP base moves increasingly to the right. Romney announced in September that he would not seek reelection to the Senate.

DeSantis graduated in 2005 from Harvard Law, where one classmate described him as a "conservative, but not particularly outspoken."

"Quiet guy ... kept to himself," another former classmate said, speaking on the condition of anonymity. "[DeSantis] did not really become part of the social fabric of the law school community at all -- to the extent he had friends, it was the Federalist Society crowd," referring to the conservative legal group.

Another former classmate recalled that DeSantis took pride in making it to the Ivy League, where he attended Yale as an undergrad before getting into Harvard Law. "He was for sure proud of making it here," a former Yale classmate, who described DeSantis as a typical "jock," told ABC News.

DeSantis has since bashed his prestigious education, writing in his book "The Courage to Be Free" earlier this year that his degrees from Yale and Harvard are "political scarlet letters."

Romney has also taken jabs at DeSantis, most recently in a series of interviews with his biographer, McKay Coppins. Romney said DeSantis "looks like he's got a toothache" on the campaign trail and "there's just no warmth at all."