The comments, made in an exclusive interview with ABC News' George Stephanopoulos, could galvanize reform advocates who argue that the legislative filibuster is stymying Biden's agenda in the narrowly divided Senate.
"Aren't you going to have to choose between preserving the filibuster, and advancing your agenda?" Stephanopoulos asked Biden in their interview outside Philadelphia.
"Yes, but here's the choice: I don't think that you have to eliminate the filibuster, you have to do it what it used to be when I first got to the Senate back in the old days," Biden said. "You had to stand up and command the floor, you had to keep talking."
"So you're for that reform? You're for bringing back the talking filibuster?" Stephanopulos asked.
"I am. That's what it was supposed to be," Biden said.
"It's getting to the point where, you know, democracy is having a hard time functioning," Biden told Stephanopoulos.
As recently as Tuesday, White House press secretary Jen Psaki insisted that Biden preferred "not to make changes" to the filibuster but was "open to hearing" ideas on the topic.
Currently, 60 votes are needed in the Senate to end debate and pass legislation, a threshold that requires Democrats to have the support of at least 10 Republicans to advance bills through the 50-50 Senate.
Many Democrats, worried that the filibuster could hold up major agenda items such as voting rights and immigration reform, have pressured Democrats to use their majority to eliminate the filibuster or alter the rules. One proposal referenced by Biden on Tuesday, would revert back to the "talking filibuster" used decades ago that required senators to speak on the Senate floor to sustain a challenge to legislation.
While moderate Democratic Sens. Joe Manchin, D-W.Va., and Kyrsten Sinema, D-Ariz., have objected to changing the filibuster, Manchin recently raised the possibility of making the tactic more "painful" for Republicans – a comment seized on by the reform advocates.
Senate Minority Leader Mitch McConnell, R-Ky., on Tuesday warned Democrats against changing the legislative filibuster.
"This chaos would not open up an express lane to liberal change. It would not open up an express lane for the Biden presidency to speed into the history books," he said. "The Senate would be more like a hundred-car pile-up. Nothing moving."
McConnell said Republicans would take advantage of any rule changes the next time they retained the Senate majority.
"This pendulum would swing both ways — hard," he said.
Watch more of the interview with President Joe Biden on ABC's "Good Morning America" on Wednesday, March 17, at 7 a.m. EDT.