"He has been one of the most transformative Presidents in our collective lifetime," he said Thursday at a Biden fundraiser in west Michigan.
Newsom was one of about two dozen Democratic governors who met with Biden last night at the White House, where the president worked to reassure them he is still a viable candidate against former President Donald Trump.
According to one person who was in the meeting, Biden told the governors that he needs to get more rest and in order to get more sleep, he wants to stop scheduling events past 8 p.m.
Newsom though says Biden was far from the person America saw on the debate stage a week earlier.
President Biden vows to stay in race after medical checkup: sources
"That was the Joe Biden I remember from two weeks ago. That was the Joe Biden I remember from two years ago. That's the Joe Biden I'm looking forward to re-electing to President of the United States," Newsom told the crowd, spurring applause and cheers.
Biden took his argument to the airwaves this morning, downplaying his poor debate performance.
"I screwed up," he said on a Wisconsin radio station. "I had a bad debate, but 90 minutes on stage does not erase what I've done for three and a half years."
The president also trying to shift the focus to his opponent, pointing out Trump's numerous lies in the debate and his threats to democracy.
"I got a guy I'm running against who is embracing political violence, pledging to rule as a dictator on day one," said Biden.
But Democrats are increasingly nervous that Biden will lose to Trump and cost the party control of the House and Senate.
A second Democratic lawmaker, Rep. Raul Grijalva of Arizona, now says Biden should "get out of this race," telling the New York Times: "If he's the candidate, I'm going to support him, but I think that this is an opportunity to look elsewhere."
Others say Biden's handlers have to step aside and put him out in front of the cameras.
"He's got to show the American people that he can do this job, and he can't be wrapped in bubble right now," said Michigan Rep. Debbie Dingell.
Meanwhile, Trump appears to be basking in the current chaos of the Democratic party. He posted a video online where he falsely claims Biden is leaving the race, and then bashes Vice President Kamala Harris.
"She's so bad," he said in the recording. "She's so pathetic. She's just so f------ bad."