Milo Yiannopoulos has resigned from Breitbart News after coming under fire over his comments on sexual relationships between boys and older men.
The Conservative Political Action Conference withdrew its invitation to the controversial alt-right commentator on Monday after video of his remarks was promoted through social media.
Publisher Simon & Schuster and its Threshold Editions imprint later announced it would cancel the publication of his book, Dangerous.
Yiannopoulos, 32, said at a news conference on Tuesday he was quitting as editor of Breitbart Tech because it would be wrong "to allow my poor choice of words to detract from my colleagues' important reporting".
"I regret the things that I said," Yiannopoulos said, while calling the furore over his comments a "cynical media witch hunt".
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He said other publishers were interested in his book and announced he would launch a new media company.
In the video, a 2016 episode of podcast The Drunken Peasants, Yiannopoulos discussed his own experience with sexual assault as a teenager.
He argued in the clip that relationships between "younger boys and older men" could be beneficial.
Yiannopoulos has built a media profile out of outrageous statements and comments on feminists, Muslims and Black Lives Matter activists that have been criticised as sexist and racist.
His appearances have triggered protests on US college campuses, including a demonstration earlier in February that turned violent at University of California at Berkeley, forcing the event's cancellation.
Breitbart News is considered by many a platform for the so-called "alt-right" movement, an offshoot of conservatism that mixes racism, white nationalism and populism.
The media company was previously run by Steve Bannon, who is now a senior adviser in the Trump White House.
