The gay alt-right provocateur quit following the release of a past interview, in which he appeared to endorse pedophilia. As a result, Simon & Schuster killed his book deal. He was also disinvited from the Conservative Political Action Conference.
In a statement obtained by BuzzFeed News, Yiannopoulos said he resigned in order to "do right" by his colleagues at the conservative news site, which was formerly run by White House chief strategist Stephen Bannon. Yiannopoulos was a senior editor.
"Breitbart News has stood by me when others caved. They allowed me to carry conservative and libertarian ideas to communities that would otherwise never have heard them. They have been a significant factor in my success. I'm grateful for that freedom and for the friendships I forged there.
"I would be wrong to allow my poor choice of words to detract from my colleagues' important reporting, so today I am resigning from Brietbart, effective immediately. This decision is mine alone.
"When your friends have done right by you, you do right by them. For me, now, that means stepping aside so my colleagues at Breitbart can get back to the great work they do."
At a Tuesday press conference in New York City, Yiannopoulos called himself "a warrior for free speech and creative expression." He also promised the launch of "a new, independently funded media venture of my own and a live tour in the coming weeks."
"I'm going to focus now on entertainment, on education ... and less on journalism," Yiannopoulos added.
Yiannopoulos, an ardent supporter of Donald Trump, first rose to infamy after he was banned from Twitter for provoking a racist and sexist social media campaign against Ghostbusters actress Leslie Jones. Since then, he has taken his incendiary remarks on a tour of college campuses, which has brought out protesters.
However, the last straw occurred over the weekend, when a group called the Reagan Battalion, which bills itself as a conservative news source, released a 2016 interview from a podcast called The Drunken Peasants.
In it, Yiannopoulos denounced the "arbitrary and oppressive idea of consent" and said, "People are messy and complex, and actually in the homosexual world particularly, some of those relationships between younger boys and older men, those coming-of-age relationships, the relationships in which those older men have helped those young boys to discover who they are and give them security and safety and provide them with love and a reliable, a rock, where they can't speak to their parents."
He also said such relationships do not constitute pedophilia. "Pedophilia is not an attraction to somebody who is 13 years old who is sexually mature," he said. "Pedophilia is an attraction to children who have not reached puberty." And after describing an experience that the host said sounded like molestation by a priest, Yiannopoulos said, "I'm grateful for Father Michael. I wouldn't give nearly such good head if it wasn't for him."
In the wake of these remarks, Yiannopoulous's publisher announced Monday that it would be canceling its planned release of his memoir, Dangerous.
"After careful consideration, Simon & Schuster and its Threshold Editions imprint have cancelled publication of Dangerous by Milo Yiannopoulos," the publisher said in a statement.
Simon & Schuster sparked a public outcry when it offered the $250,000 book deal to Yiannopoulos last year. In protest, feminist author Roxane Gay withdrew a forthcoming book from Simon & Schuster, and she has continued to speak out against the publisher for making what amounted to a business decision rather than a moral one.
"Simon & Schuster realized it would cost them more money to do business with Milo than he could earn for them," Gay wrote on Tumblr. "They were fine with his racist and xenophobic and sexist ideologies. They were fine with his transphobia, anti-Semitism and Islamophobia. They were fine with how he encourages his followers to harass women and people of color and transgender people online."
Early Tuesday, the editor in chief of Breitbart, Alex Marlow, called Yiannopoulos's remarks "indefensible" on the site's daily radio show.
"It's all very upsetting and something we take very seriously at Breitbart. We've been going through things and trying to figure out the best way to handle this, but the bottom line is the comments on the video are not defensible, and I think most people [agree] with that," Marlow said.
In response to the outcry over the video, Yiannopoulos posted what he called a "note for idiots" on Facebook. "I do not support pedophilia. Period," he wrote. "It is a vile and disgusting crime, perhaps the very worst. There are selectively edited videos doing the rounds, as part of a co-ordinated effort to discredit me from establishment Republicans, that suggest I am soft on the subject. If it somehow comes across (through my own sloppy phrasing or through deceptive editing) that I meant any of the ugly things alleged, let me set the record straight: I am completely disgusted by the abuse of children."
He reiterated these remarks at the Tuesday press conference.
"I will not apologize for dealing with my life experiences in the best way that I can, which is humor. No one can tell me or anyone else who has lived through sexual abuse how to deal with those emotions," he said. "But I am sorry to other abuse victims if my own personal way of dealing with what happened to me has hurt you."