The two politicians faced off in Cleveland, Ohio, for the highly anticipated first televised debate just over a month before the election.
During an acrimonious and chaotic showdown, Mr Trump and Mr Biden exchanged verbal blows while the moderator, Chris Wallace, struggled to take control.
At one point, Mr Trump was asked to disavow white supremacists and the Proud Boys, a far-right organisation, but instead told them to “stand back and stand by”.
His apparent unwillingness to issue a blanket condemnation of white supremacy brought sharp and immediate criticism online, including from celebrities.
In a stinging response, Frozen star Josh Gad, who is of Jewish descent, said: “The Nazis killed my family members. Tonight Trump told them to ‘stand by.’ I have never imagined saying these words in my life. ‘Mr. President, F*** YOU.'”
Actress Kerry Washington, best known for her work on political drama Scandal, tweeted: “Once again. He refuses to condemn White supremacy. PAY ATTENTION FOLKS. Please vote.”
Comedian and actress Robin Thede also accused Mr Trump of failing to condemn white supremacy, adding: “He encouraged it. The end. There are no two sides to this.”
Singer Christina Perri tweeted: “We just watched the president of the united states UNABLE and UNWILLING to condemn white supremacy. you all just saw and heard that.”
The Boys star Jack Quaid said: “He literally couldn’t denounce white supremacy.”
Zach Braff, best known for his work on TV comedy Scrubs, tweeted: “Only honest thing I digested: Nazis standby!”
And actor Patrick J Adams, the Duchess of Sussex’s former Suits co-star, said: “He just refused to condemn white supremacy. That just happened right?”
Perhaps unsurprisingly, the verdict from Hollywood was in favour of Mr Biden.
Many stars – include Mark Ruffalo, John Legend and Pete Davidson – were critical of the president.
“We can’t put ourselves through another 4 years of this walking dumpster fire,” Legend, a frequent critic of Mr Trump, said.
The debate – which was marred by frequent interruptions from Mr Trump – included segments on the coronavirus pandemic, healthcare and climate change.
Marvel star Ruffalo, a climate change activist, criticised Mr Trump’s environmental record and said “he has no leadership qualities, he has shown that all he can do is denigrate and lie”.
And best-selling author Stephen King, another vocal critic of the president, said: “You’ve got a decent man vs. a hulking, loudmouth bully with no specific plans on anything.”