The presidential hopeful tweeted a campaign video featuring footage from a recent episode of The Joe Rogan Experience in which the podcast presenter said: “I think I’ll probably vote for Bernie”.
“I believe in him, I like him a lot,” explained Mr Rogan, during a discussion of the Democrat primaries with New York Times journalist Bari Weiss.
“He’s been insanely consistent his entire life,” he added. “He’s basically been saying the same thing, been for the same thing his whole life. And that in and of itself is a very powerful structure to operate from.”
The endorsement in a high-profile podcast, which attracts millions of viewers on YouTube, could help bolster support for Mr Sanders, who has enjoyed a surge in support in recent polling.
But Mr Rogan has been accused of transphobia and sexism for comments made on his podcast and social media, and has also faced criticism for inviting far-right figures such as Milo Yiannopoulos and Infowars conspiracy theorist Alex Jones on to his show.
In 2013, he said there was “no f**king way” a transgender MMA fighter should be allowed to compete against other women because “she’s a f***ing man”, adding: “I don’t care if you doing have a dick anymore”.
Later the same year he tweeted that he hoped men who called themselves feminist “choke to death on vegan pizza while crying over a lady gaga song”.
The incorporation of Mr Rogan’s endorsement into an official 2020 campaign video led to Mr Sanders being accused of validating those views.
“His endorsement of your campaign is an embarrassment, not a point of pride,” tweeted writer Ella Dawson, a supporter of the senator’s Democrat rival Elizabeth Warren.
Activist Alexis Goldstein wrote: “I really like Bernie and am disappointed to see the campaign boost Rogan, who has made some very anti-trans comments. I really hope the campaign reconsiders.”
However, others defended Mr Sanders and said the Democrats needed to embrace a broad church.
Ryan Grim, Washington DC bureau chief at news website The Intercept, said: “Rogan is a part of our politics and has millions of people who listen to him, nothing you do can change that. You can either have him in the Sanders tent in conversation with people with decent values or cast him out into the arms of Trump. The latter will do far more harm.”
Charlotte Clymer, press secretary for the Human Rights Campaign, said she believed the Sanders campaign team “weren’t aware of Joe Rogan’s transphobia” but called for them to “acknowledge that Rogan is a transphobe and move away from this”.
Mr Rogan, a former UFC commentator, has amassed a huge and loyal following through his podcasts, which have nearly 7.3 million subscribers on YouTube alone and consistently rank near to top of iTunes download charts.
An article by The Atlantic last year pointed to the influence his endorsement could potentially have.
“There’s no real way to describe ‘Joe Rogan fans,’ wrote Devin Gordin. “They’re not aligned around any narrow set of curiosities or politics. They’re aligned around Joe.”