The move marks a notable shift from President Donald Trump, whose own scepticism of mask-wearing has contributed to a politicisation of the issue.
President-elect Mr Biden has frequently emphasised mask-wearing as a “patriotic duty” and during the campaign floated the idea of instituting a nationwide mask mandate.
Joe Biden fractures his foot playing with one of his dogs
He later acknowledged a mandate would be beyond the ability of the president to enforce.
Speaking with CNN’s Jake Tapper, Mr Biden said he would make the request of Americans on Inauguration Day, January 20.
“On the first day I’m inaugurated, I’m going to ask the public for 100 days to mask. Just 100 days to mask – not forever, just 100 days,” He said.
“And I think we’ll see a significant reduction” in coronavirus, Mr Biden said.
Mr Biden also said he asked Dr Anthony Fauci to stay on in his administration, “in the exact same role he’s had for the past several presidents”, as the director of the National Institute of Allergy and Infectious Diseases, the nation’s top infectious-disease expert.
The president-elect said he has asked Dr Fauci to be a “chief medical adviser” as well as part of his Covid-19 advisory team.
Regarding a coronavirus vaccine, Mr Biden said he would be “happy” to get inoculated in public to assuage any concerns about its efficacy and safety.
Three former presidents – Barack Obama, George W Bush and Bill Clinton – have said they would also get vaccinated publicly to show that it is safe.
“People have lost faith in the ability of the vaccine to work,” Mr Biden said, adding that “it matters what a president and the vice president do”.