His aim was to salvage his governorship.
The most prominent white men in the potential Democratic field, Biden and Vermont Sen.
"It doesn't matter if he is a Republican or a Democrat". Northam, a liberal star, has now turned out to be a fraud and a phony.
Mr Northam, standing with his wife Pam, said he believed it was possible some photographs in the yearbook had been switched. "And I was unaware of what was on my page". The Congressional Black Caucus, the Virginia Legislative Black Caucus and the civil rights group NAACP said Northam's press conference did little to change their position.
Northam defeated Gillespie by about 9 percentage points, but Trump says Gillespie would have won by 20 points if someone had found the photo.
The Democratic National Committee, Democratic Governor's Association, Virginia state and House Democrats, and leading Democratic politicians have all called on Northam to immediately resign over the controversy.
"There aren't two sets of rules for our friends and our foes: Right is right and wrong is wrong ... and racism can not be excused in our government or anywhere else", she wrote.
Chandler described the Governor's medical school year book photo, showing one man dressed in blackface and another in KKK robes, as a "betrayal".
Northam added that he moonwalked for the show.
"I am not the person in the photo that caused a stir yesterday", Northam said.
He added that he once used shoe polish to darken his face for a Michael Jackson costume he wore in a 1984 dance contest in San Antonio, Texas, when he was in the US Army. "I think that he understands where people are coming from, but he knows where we need to go". "You remember these things", he said.
The head of Mr Northam's party in the state also called on him to quit. He is also the bishop and senior pastor of The Called Church in Chesapeake, Virginia.
That leaves Democrats running for president or considering bids to navigate an explosive and embarrassing story as they mount campaigns meant to serve as a contrast with racial divisions that have intensified under the presidency of Donald Trump. "And we will never hesitate to hold accountable people who violate those values, regardless of their party affiliation".
Northam took question after question at the lengthy press conference, appearing unflustered as reporters asked how he could continue to without the support of his own party.
"I have spent the past year as your governor fighting for a Virginia that works better for all people". In a statement issued later that day, Northam conceded the picture was of him and apologized. It would appear Saturday was not a hit.
"He should step down and allow the Commonwealth to begin healing", the statement from Senators Mark Warner and Tim Kaine and Representative Bobby Scott read.
"We are here today because the history of Jim Crow is still alive and living in the Governor Mansion", said community activist Art Burton, who also touched upon Richmond's racist roots as the capitol of the Confederacy during the Civil War.
He told ABC News Chief Anchor George Stephanopoulos on "This Week" that the explanation Northam offered in a news conference Saturday doesn't make a difference "at this juncture". In the case of Northam, though, there is direct evidence of his past actions. The current lieutenant governor, Justin Fairfax, is only the second African American elected to statewide office in Virginia.