The former vice president took in the Keystone state’s 20 electors, NBC News, and CNN reported on Saturday.
The victory in Pennsylvania put Biden past the 270 electoral votes needed to win the White House and defeat President Donald Trump.
Biden, 78, will become the oldest US president when he is sworn in on January 20 in the midst of the worst public health crisis in a century, the deepest economic recession since the 1930s and a national reckoning with racism.
Senator Kamala Harris, who was Biden’s running mate, will also become the first female, first Black and first Asian American vice president.
In addition to the projected electoral victory, Biden has also garnered more popular votes than Trump, setting a record for the most votes of any candidate in US history.
His election will condemn Trump, who has had a longstanding obsession with winning, to the ranks of one-term presidents in America.