Steve Bannon is stepping down as executive chairman of Breitbart News Network, in the wake of the furor over quotes he made in Michael Wolff’s book “Fire and Fury: Inside the Trump White House.”

His departure marks a spectacular turn of events for someone who, just a year ago, was regarded as Trump’s most influential adviser and, in the months after he left the administration, a leading voice of the nationalist right.

In an announcement, the site said that “Bannon and Breitbart will work together on a smooth and orderly transition.”

“I’m proud of what the Breitbart team has accomplished in so short a period of time in building out a world-class news platform,” Bannon said in a statement.

A Breitbart spokeswoman did not return a request for comment.

Larry Solov, Breitbart CEO, said, “Steve is a valued part of our legacy, and we will always be grateful for his contributions, and what he has helped us to accomplish.”

SiriusXM also announced on Tuesday that it was ending its controversial relationship with Bannon as he steps down from the site. “Breitbart News has decided to end its relationship with Stephen K. Bannon, therefore he will no longer host on SiriusXM since our programming agreement is with Breitbart News,” the company said in a statement.

Bannon’s future has been in doubt since last week, when Rebekah Mercer, one of the investors in the site and one of Bannon’s political allies, parted ways with him. She issued a public statement saying that “my family and I have not communicated with Steve Bannon in many months and have provided no financial support to his political agenda, nor do we support his recent actions and statements.”

Bannon was a major source in Wolff’s book, which depicts President Donald Trump as unprepared and unfit for the presidency, with even his lost loyal advisers questioning his temperament and behavior. In the book, Bannon characterizes as “treasonous” and “unpatriotic” a June, 2016 meeting that Donald Trump Jr. arranged with a group of Russians.

Trump issued a scathing statement attacking Bannon, and while Bannon made a statement of regret over the weekend, reaffirming his support for the president, the White House has made clear that they did not believe that relations could be repaired.

“I don’t believe there’s any way back for Mr. Bannon at this point,” said White House spokesman Hogan Gidley. “It is very obvious that Mr. Bannon worked with Mr. Wolff in this particular book.” Trump himself began to refer to him as “Sloppy Steve,” a reference to Bannon’s deshelved attire and unshaven look.

Bannon, however, shared much in common with Trump — a brashness, a knack for opportunism and an eagerness for the political attack. He seemed to relish the attention as liberals frequent punching bag.

Bannon was named executive chairman of Breitbart News in 2012, shortly after the death of founder Andrew Breitbart. At the time, he had been a conservative documentary filmmaker, having spent much of the 1990s as a producer and investment banker.

He helped raise the profile of Breitbart in the 2016 election cycle, as it became an unabashed champion of Trump’s presidential aspirations and pushed right and even far right positions on issues like immigration, trade and economic nationalism. He himself once called it the “platform for the alt-right,” although other editors bristled at the connection. Web traffic climbed.

His friendship with Trump paid off in August, 2016, when the Republican nominee named him campaign CEO as part of a staff shakeup.

After Trump’s victory, Bannon was named chief strategist, and in the early weeks of the administration he was regarded as the architect of the president’s agenda. Time put him on the cover and labeled him, “The Great Manipulator,” and “Saturday Night Live” portrayed him as the grim reaper. In his West Wing office, Bannon kept a white board of Trump’s campaign promises.

But he sparred with other top advisers, like economic adviser Gary Cohn and National Security Adviser H.R. McMaster, and characterized his efforts as one of a nationalist fighting the globalists in the D.C. and media establishments.

Bannon fell out of disfavor during the summer and, with the new chief of staff John Kelly, speculation intensified that his days were numbered. He left the administration in August. It was then that he returned to Breitbart News.

At the time, Bannon vowed to continue to fight the Republican establishment, as he set out on a mission to recruit far-to-the-right challengers to GOP incumbents. But his choice in an Alabama special election, Roy Moore, proved to be a political hot potato, especially after he was accused to pursuing sexual relations with teenage girls when he was in his 30s. Moore lost and gave Democrats their first Senate win the state in 25 years.

Bannon also was a regular presence on SiriusXM, which featured Breitbart programming on its news channel. A spokesman for the satellite radio network said that “Breitbart News has decided to end its relationship with Stephen K. Bannon, therefore he will no longer host on SiriusXM since our programming agreement is with Breitbart News.”