It was the first time Trump had been seen since he survived an assassination attempt at a rally in Pennsylvania on Sunday.
The former president, who was formally anointed as the Republican presidential nominee, was seen alongside Senator JD Vance, his vice-presidential pick announced earlier today.
Biden bore a square white bandage over one ear, which had been left bleeding after Thomas Matthew Crooks opened fire at Trump on the podium, killing one rally attendant and injuring two others.
Former White House physician Ronny Jackson said he medically assessed Trump’s wound bandaged him up earlier today.
During an interview on “The Benny Show” podcast, the Texas congressman said he “checked out” Trump’s ear and “there was no concussive effect from the bullet” because it was far enough from Trump’s head.
“It just took the top of his ear off, a little bit of the top of his ear off, as it passed through,” he said.
“It was bleeding like crazy.”
Jackson said that Trump’s injury is “dressed up. He’ll be okay … it’s going to granulate and heal in, and he’s not going to need anything to be done with it.”
Trump was greeted with cheers and a chant of “Fight, fight, fight, fight” – the same word he mouthed to supporters as he was ushered off the podium by Secret Service agents on Sunday.
He smiled around at the packed convention floor, waving and pumping his fist.
Trump’s arrival at about 9pm local time (noon AEST) coincided with a speech by self-proclaimed “regular guy” Mark Laws, from Michigan, one of the speakers at the convention.
Trump makes first public appearance since attempted assassination
Trump was also present for the speech by keynote speaker Amber Rose, a model, rapper and TV host who had previously been a vocal Trump detractor.
Rose, endorsed Trump in May this year, and said at the convention that Americans were “safer, wealthier, and stronger” under a Trump presidency.