The actor and former wrestler made the announcement in a video shared on his social media accounts, in which he is seen interviewing the candidates over video chat.
The clip begins with Johnson saying that this is “arguably the most critical election [the US] has seen in decades”.
“[Endorsing] is something that I’ve certainly not done in the past, so I’m gonna go big,” he said. “You guys know me: if I go, I go big.
“As a registered independent for years now with centrist ideologies, I do feel that vice president Biden and senator Harris are the best choice to lead our country, and I am endorsing them to become president and vice president of our united states.”
This short clip of Johnson addressing the camera is followed by a sit-down with Biden and Harris, which the actor described as a “great and extremely productive conversation”.
Johnson also quoted his late father, Canadian wrestler Rocky Johnson, who died of a pulmonary embolism earlier this year.
“You know, this past January,” he said, “approximately nine months ago, my old man died. And I didn’t get the chance to say goodbye to him.
As a political independent & centrist, I’ve voted for both parties in the past. In this critical presidential election, I’m endorsing @JoeBiden & @KamalaHarris.
Progress takes courage, humanity, empathy, strength, KINDNESS & RESPECT.
We must ALL VOTE: https://t.co/rZi1mxh8DC pic.twitter.com/auLbc8xDBv
— Dwayne Johnson (@TheRock) September 27, 2020
“But he always said that respect is given when it’s earned. So you gotta get out there and you gotta earn it, with your own two hands.”
Johnson also suggested that he would continue to discuss politics in the months to come.