And what a chaotic and combative 90 minutes it turned out to be.
Trump seemed to be unwilling to accept the conditions of the debate, whereby each candidate is allowed 2 minutes to answer specific questions posed to them.
From the outset, the current president interrupted so frequently, that a visibly exasperated Biden said about 20 minutes into the debate: "Would you shut up, man?"
Moderator Chris Wallace also found it difficult to keep Trump's constant interruptions under control, leading the debate to evolve into an embarrassing spectacle that still has many viewers and media pundits scratching their heads, trying to understand what exactly transpired.
Wallace cautioned Trump several times to stop interrupting and let Biden speak.
“Frankly, you’ve been doing more interrupting,” Wallace said at one point. He even asked if the president wanted to change seats and become the moderator.
For about 15 minutes, the two candidates did settle into more typical debate banter, but it didn't last long, with the president starting to interrupt and talk over Biden and Wallace again.
"It's hard to get any word in with this clown," Biden said, throwing up his hands.
But the mud-slinging was just getting started.
Biden called Trump a "racist" when the two men debated race relations and called him the "the worst president America has ever had."
As Trump kept interrupting, Biden tried to get back on track. “Here’s the deal. Here’s the deal,” Biden repeated, before asserting that he was not on stage to “call out his lies.”
“Everybody knows he’s a liar,” Biden said.
The president leveled barrages of unfounded accusations against his Democratic rival and his family, invoking his son Hunter Biden's work in Ukraine and bringing up the younger Biden's history of drug abuse. Mr. Trump declined to condemn white supremacist groups and defended his response to the coronavirus pandemic that has claimed more than 200,000 American lives, trying to portray Biden as a socialist who isn't equipped to occupy the Oval Office.
"Did you use the word smart?" the president asked Biden at one point. "You graduated either the lowest or almost the lowest in your class. Don't ever use the word smart with me, Joe."
Biden, for his part, tried to direct his answers to the audience watching at home.
"This is a president who has used everything as a dog whistle to try to generate racist hatred, racist division," Biden said.
Six in 10 debate watchers said former Vice President Joe Biden did the best job during the debate, and just 28% say President Donald Trump did, according to a CNN poll of debate watchers conducted by SSRS.
Here are the highlights from the Trump, Biden debate: