He has been charged with second degree murder, three counts of malicious wounding and failing to stop at an accident which caused a death, Kumer said in an email.
Donald Trump condemned the violence on several sides, but faced criticism for failing to directly denounce the far-right demonstrators.
In a different incident, two police officers died when their helicopter, which was tracking the rally, crashed outside Charlottesville.
State police said the helicopter assisted public safety resources. The pilot, Lieutenant H Jay Cullen, 48, of Midlothian, Virginia, and Trooper-pilot Berke Bates of Quinton, Virginia, died at the scene.
The deaths came at the end of a day marked by clashes between people and far-right nationalists who had come to protest against their job of a downtown park containing a statue of the Confederate general Robert E Lee.
Witnesses said the white supremacist rally was being peacefully protested by those and footage revealed the vehicle crashing into another vehicle, throwing people over the top of it.
The photographer Pat Jarrett, who witnessed the incident, said: A grey Dodge Charger plowed to a sedan and then into a minivan. Bodies flew. People crying and were terrified. Those closest to it said it was clearly a violent assault. The motorist, who people later described as a white guy with a straggly beard, drove off and turned out from there, the front end of his car all smashed up.
Charlottesville mayor Mike Signer tweeted: I am heartbroken that a life has been lost here. I urge all people of good will go home.
Speaking at a press conference on Saturday evening, the governor of Virginia, Terry McAuliffe, who had earlier declared a state of crisis, advised the white supremacists: Go home Shame on you. You’re anything but a patriot, although you pretend you’re patriots.
The mother of James Fields, the man arrested for driving the vehicle, told the Associated Press on Saturday night that she knew her son was attending a rally in Virginia but didnt know it was a white supremacist rally.
I thought it had something to do with Trump. Trumps not a white supremacist, Samantha Bloom said, before getting visibly upset as she learned of the deaths and injuries in the rally He had an African-American friend so …, she said before her voice trailed off.
Responding to the events in Charlottesville from Bedminster, New Jersey, the US president said: We condemn in the strongest possible terms this egregious display on sides on sides, of violence, bigotry and hatred.
But the Republican senator Marco Rubio tweeted that it was important for Trump to describe the events as a terror attack by white supremacists.
The FBI said it was opening a civil rights investigation into the accident along with the Justice Departments civil rights department and the district attorneys office.
The US attorney general, Jeff Sessions, said: The deaths and violence in Charlottesville strike at the core of American law and justice. They betray our core values when such activities arise from hatred and racial bigotry and cannot be tolerated.
The automobile attack came about two hours after state police in riot gear had cleared Emancipation Park, the site of the Robert E Lee statue. The citys decision in February to remove the statue drew protests from the alt-right and the Ku Klux Klan.
Riot police cleared the park . The far-right groups were largely compliant, but had to run the gauntlet of counter-protesters as they walked west along Market Street.
After a stalemate that was short, a hard core of about 100 protesters that were far-right moved into a park two miles away and gathered to listen to speakers who had been scheduled for the Unite the Right occasion.
Among the speakers, the figurehead Richard Spencer, lashed out at city and police authorities and said he had been maced on the way in.