Arianna Huffington announced that she is stepping down as editor-in-chief of The Huffington Post.

Arianna Huffington, the Greek American journalist who founded the Huffington Post, said Thursday she will step down as editor-in-chief to start a new venture, ending her groundbreaking and controversial 11-year reign at the liberal online news company.

Huffington, 66, has held talks in recent weeks with venture capitalists to fund her new media company, Thrive Global, which will launch in November and provide content and training seminars on wellness. Thrive closed a new round of funding, led by other co-founders of the Huffington Post, she said.

The Huffington Post didn’t immediately name her replacement. In a staff memo, Tim Armstrong, CEO of AOL, which owns the Huffington Post, said an interim editorial committee of other top editors will perform Arianna’s role for now and be involved in an ongoing search for a new editor-in-chief.

“When I decided to create Thrive Global, I thought it would be possible to build a startup and continue as editor ­in ­chief of the Huffington Post,” Huffington said in a statement. “Today, it’s clear that was an illusion. As Thrive Global moved from an idea to a reality, with investors, staff, and offices, it became clear to me that I simply couldn’t do justice to both companies.”

Her departure creates a whopping, if not unexpected, void, at the Huffington Post, a pioneering news venture that had an immense impact on the way online newsrooms publish around the world. Founded in 2005 as a liberal alternative to the conservative news aggregator site, the Drudge Report, the Huffington Post drew heavy criticism for repackaging other news agencies’ stories with click-bait headlines and posting blogs written by unpaid contributors. But its tactics were widely imitated by other news startups and traditional media companies that are eager to boost online traffic.

But in recent years, the Huffington Post began enlarging its staff to pursue original reporting and broadened its coverage to include new topic “verticals,” such as online commentary, video and “What’s Working,” a channel about solutions and inspirational news. Its domestic editorial staff, now about 350, would outnumber most other U.S. newsrooms. In 2012, it won the Pulitzer Prize for a series on wounded veterans.

In 2011, she and other shareholders of the Huffington Post sold it to AOL for about $315 million. She was then named president and editor-in-chief of the newly created Huffington Post Media Group, which houses her site and other AOL digital news properties, such as Engadget, TechCrunch and MapQuest.

Her role and influence in the combined company have been questioned repeatedly amid reports that she and Armstrong were frequently at odds about the direction of the new media group. The management structure became more complicated when Verizon paid $4.4 billion to buy AOL last year. Earlier this year, Verizon expanded its media business by agreeing to pay $4.8 billion to buy Yahoo’s web properties, including Yahoo Finance and Yahoo News.

Huffington stayed on after the Verizon-AOL deal closed, but signs that she was restless and ready for new ventures emerged in recent years. In 2010, she gave a Ted Talk speech about the importance of sleep and wrote a book this year about the topic, The Sleep Revolution: Transforming Your Life, One Night at a Time. Last year, she authored another book on well-being, Thrive: The Third Metric to Redefining Success and Creating a Life of Well-Being, Wisdom, and Wonder. The idea for a related startup company soon followed.

“Arianna is a visionary who built The Huffington Post into a truly transformative news platform,” Armstrong said. “AOL and Verizon are committed to continuing its growth and the groundbreaking work Arianna pioneered.” 

Thrive Global’s Series A funding, its first significant round of raising funds, was led by Lerer Hippeau Ventures, which was founded by Kenny Lerer and Eric Hippeau. Lerer and Hippeau have a long working relationship with Huffington. Lerer was co-founder of the Huffington Post and Hippeau was its CEO when it was acquired by AOL.

Other investors include Blue Pool Capital, Greycroft Partners, Bridgewater CEO Ray Dalio, Mohamed El-Erian (formerly with PIMCO), NBA player Andre Iguodala, and entrepreneur Sean Parker.

Follow USA TODAY media reporter Roger Yu on Twitter @ByRogerYu.