Trump made a string of false claims, suggested he would not accept the results of the election were he to lose in November and was forced to say: “I did not have sex with a porn star” when Mr Biden pressed him on his alleged affair with adult film actress Stormy Daniels.
One of the most farcical moments of the debate came when the two men began bickering about golf when asked about concerns over their ages.
Trump, who claims to have a handicap roughly half of that of a professional golfer, said Mr Biden had failed to answer his challenge to a round of golf and “can’t hit a ball 50 yards”.
Mr Biden fired back, telling him: “I’d be happy to have a driving contest. I got my handicap when I was vice president down to a six.
“By the way, I told you before, I’m happy to play golf with you if you carry your own bag. Think you can do it?”
“That’s the biggest lie – that he’s a six handicap – of all,” Trump answered,
“You are a child”, Mr Biden said back, injecting a rare moment of energy into the debate.
“I’ve seen your swing. I know your swing,” he said eventually, adding: “Let’s not act like children.”
“You are a child,” the president hit back angrily.