A gunman murdered 19 students and two teachers at the Robb Elementary School in the Texas city last May, with police heavily criticised for their slow response in taking down the shooter.
Mr Biden, who was joined by first lady Dr Jill Biden for the White House speech, said that at the scene of each mass shooting he attended, he was told the same thing by the families of victims.
“At each place, you hear the same message ‘Do something, for God’s sake do something,’” he said.
“We did something afterwards but not nearly enough. We still need to ban, in my view, AR-15 assault weapons once again, you know they have been used time and again in mass killings of innocent children and people.”
And Mr Biden, who visited Uvalde after the shooting, called on politicians to do more to end the gun crisis in the United States.
“We can’t end this epidemic until Congress passes some common sense gun safety laws... How many more parents will live their worst nightmare,” he said.
The president, who has lost two children of his own, told the families that he realised that the anniversary represented a “really tough day” for them.
“Remembering is important but it is also painful,” said the president, who was surrounded by a lit candle for each victim of the mass shooting.
“A year of missed birthdays, school plays and soccer games, just that smile. A year of everyday joys gone forever.”
A criminal investigation into the actions of law enforcement reaction to the shooting remains underway in Texas, where it is the worst school shooting in the state’s history.
A report by state lawmakers concluded that nearly 400 officers from federal, state and local agencies responded to the school but that those heavily-armed officers waited an hour to confront and kill the 18-year-old gunman.
The report accused Uvalde police of failing “to prioritize saving innocent lives over their own safety.”
Mr Biden has now made more than 70 unanswered calls for Congress to take action and ban assault weapons, which are commonly used in mass shootings in the country.
It’s a demand he has given lawmakers dozens of times since entering office in 2021. Within his first two years in office, there have been roughly 1,400 mass shootings.
He has referenced a federal ban on assault weapons, called on Congress to renew an assault weapons ban or pledged that his Democratic allies will do so roughly 70 times since entering office, according to The Independent’s March 2023 review of his public statements and remarks via Factba.se.