The president dropped to his knees after stumbling over a sandbag after two hours on stage at the service academy in Colorado Springs on Thursday.
Mr Biden, 80, did not appear hurt by the fall and continued to stand on stage until the ceremony ended several minutes later, according to the White House pool.
Mr Trump was informed about the fall as he campaigned in Iowa and told his supporters that it was “Not inspiring” for the Air Force graduates who had witnessed it.
“I hope he wasn’t hurt. I hope he wasn’t hurt...You don’t want that,” said Mr Trump, who then recalled his own difficult moment when he had to carefully tip-toe down a ramp at the Army’s West Point graduation ceremony in 2020.
“The whole thing is crazy, you have got to be careful about that, you don’t want that even if you have to tip-toe down a ramp,” he added as he recalled the ramp was “like an ice-skating rink.”
Mr Trump’s online followers were less understanding of Mr Biden’s fall, taunting him on Twitter.
“Biden falls up a flight of stairs, falls off a bike, falls on a stage... and the MSM says nothing. Trump gets a bigger salt shaker than everyone else and it’s an MSM feeding frenzy for a week,” tweeted one person.
“Laughingstock of the free world,” tweeted another user, while another critic added, “That was the loudest cheer Biden has had in years.”
“Remember the wall-to-wall apocalyptic media coverage when Trump walked slowly down a ramp? I wonder if this will get similar coverage???” Tweeted one user.
“Putin and Xi are definitely shaking in their boots at the commander in chiefs leadership,” stated another user.
“Isn’t it weird how the military on stage appear to be trying hard not to laugh and no one jumped up to help him,” added another.
Mr Biden, a Democrat, is running for re-election in 2024 and his doctors declared him fit and healthy after his February physical examination.
Earlier, during the commencement address, Mr Biden warned the graduates that they would enter military service in an increasingly unstable world, citing challenges from Russia and China.
And he predicted that Sweden would “soon” join NATO, without giving any details of their entry into the alliance.
“It will happen, I promise you,” he said,