Bill O’Reilly will depart Fox News Channel amid reports that the host and network paid millions to settle harassment cases against him, the network’s parent company announced Wednesday.

Since 1996, O’Reilly has hosted “The O’Reilly Factor,” the most-popular show on the most-watched cable news channel.

In a statement, 21st Century Fox, which owns Fox News, said it had made its decision “after a thorough and careful review of the allegations.” O’Reilly, traveling in Italy, followed late Wednesday with his own statement, which read in part, “It is tremendously disheartening that we part ways due to completely unfounded claims. But it is the unfortunate reality that many in the public eye must live with today.”

The firing follows a New York Times investigation earlier this month, which reported that Fox and O’Reilly had paid an estimated $13 million in harassment settlement claims to five women over the years, including a widely publicized one from 2004. In that particular payout — related to a charge of sexual harassment by a former associate producer at his show — Fox reportedly paid $9 million.

Since the news of the settlements broke, more than 50 advertisers had pulled their commercials from the show. The ad defections alone “were becoming too costly, so they really didn’t have a choice, said Joe Peyronnin, a Hofstra University journalism professor and former Fox News president. Many women’s rights groups also asked for O’Reilly’s dismissal.

In its internal memo to employees announcing O’Reilly’s departure, Fox said, “By ratings standards, Bill O’Reilly is one of the most accomplished TV personalities in the history of cable news. In fact, his success by any measure is indisputable. Fox News has demonstrated again and again the strength of its talent bench. We have full confidence that the network will continue to be a powerhouse in cable news. Lastly, and most importantly, we want to underscore our consistent commitment to fostering a work environment built on the values of trust and respect.”

Fox announced that “Tucker Carlson Tonight,” which now airs at 9 p.m., will move to 8 p.m. to replace “The O’Reilly Factor.” The panel talk show, “The Five,” will take Carlson’s time slot at 9 p.m.

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As the most popular personality on cable news, O’Reilly’s tenure until now was considered a lifetime one. He recently signed an extension and appeared poised to boost his already considerable Fox News profile. If not quite a friend of President Donald Trump, he has been a supporter and even advised the candidate on air during the recent political season. Trump, in turn, publicly supported O’Reilly in the wake of the harassment payment reports, calling him a “good person.”

But O’Reilly’s employer has also been in the midst of an epic succession struggle. Rupert Murdoch, founder of News Corp. and FNC ceded his role as chief executive to his son James Murdoch, 44, last year. According to a report in New York Magazine’s “Intelligencer” on Tuesday, “sons James and Lachlan have been arguing that O’Reilly needs to go [but] their father, Rupert, has resisted.” Lachlan, 45, is executive co-chairman of News Corp. and 21st Century Fox.

O’Reilly’s ouster “speaks to the internal struggle for the control of Fox News generationally within the Murdoch family,” said Mark Feldstein, a professor of journalism at the University of Maryland and author of a forthcoming book on media scandals. “But a lot of times where there is misconduct, there is always more. It’s never in isolation.”

Former Fox News chief Roger Ailes was fired last summer after the longtime FNC host and anchor Gretchen Carlson filed a sexual harassment suit against him. Carlson’s lawsuit — later settled for a reported $20 million — led the company to open an investigation, spearheaded by corporate counsel Paul, Weiss, Rifkind, Wharton & Garrison.

The investigation initiated other charges of harassment against Ailes, who exited with a reported $40 million payout. That directly led to problems for O’Reilly. Paul, Weiss set up a “hotline” for other women who wanted to file a complaint against Ailes, which led to many others, including Megyn Kelly, who has since joined NBC News.

Fox had long said no complaints were called in to the hotline about O’Reilly. But on Tuesday, Lisa Bloom — the TV legal commentator and counsel for another woman who had complained about O’Reilly’s behavior, Wendy Walsh, a former FNC guest commentator — said a call had come from an African-American woman who had requested anonymity. According to Bloom, the woman — who worked in a clerical role at Fox, but not directly for O’Reilly — said “The Factor” host would walk by her desk, and leer at her, or refer to her as “hot chocolate.”

Because the call came in on the hotline, Paul, Weiss would have been directed to investigate its veracity.

The lawyer for O’Reilly, Marc E. Kasowitz of Kasowitz Benson Torres, released a statement to the media Tuesday, as reported in the Times, which said: “It is outrageous that an allegation from an anonymous person about something that purportedly happened almost a decade ago is being treated as fact, especially where there is obviously an orchestrated campaign by activists and lawyers to destroy Mr. O’Reilly and enrich themselves through publicity-driven donation.”

Meanwhile, in February, Fox confirmed reports that the U.S. attorney’s office in Manhattan was looking into how the company had paid off the complainants. If Fox had paid the settlements out of salaries — presumably Ailes’ — then those settlements did not have to be reported to the Securities Fraud Division of the U.S. attorney’s office. According to reports, such payments would have been misleading to investors.

The departure of O’Reilly leaves a huge hole in the network’s prime-time schedule. O’Reilly has long defined the network’s personality and politics: blustery, outspoken, and refusing to cow to the so-called liberal media establishment.

Replacing O’Reilly, 67, means entering terra incognita for Fox News, which has never had to replace a prime-time figure of his magnitude. Moreover, his influence extends well beyond the screen, and into the culture at large, where he is revered or reviled. Long a lightning rod, O’Reilly always seemed to relish his role as Fox’s Peck’s bad boy. O’Reilly apologies tendered for some on-air comment or on-air crusade were so rare that they can be counted on one hand (notably in 2004, when he admitted that he had been wrong about weapons of mass destruction in Iraq).

His pugnacious style infuriated various wings of the commentariat, like Media Matters — which took to tabulating what it called his various misstatements over the years — but was, of course, embraced by his fans.

O’Reilly, who was raised in Levittown and now lives in Manhasset, fondly referred to them as “the folks,” and the folks responded in kind with on-air and off-air devotion. The show has long averaged around 3 million viewers — it has been cable’s top news show for nearly “70 quarters” in Fox lingo — 18 years. But since his troubles began earlier this year, those viewing levels appeared to grow.

His personal industry has extended to books, which number more than a dozen, most of them huge best-sellers, and the web itself, where his site, billoreilly.com, is a clearing house for news and tchotchkes, like “the best coffee mug in the world.”

But beyond numbers, books, coffee mugs, ratings and network stature, O’Reilly has had a particularly difficult-to-quantify impact on the nation at large. As the most influential commentator on cable news, he played a role in the recent election. The magnitude of that role, however, is unclear. He has long eschewed political labels for himself, and was always positioned as a self-styled populist looking out for “the little guy” — someone beyond the big East or West Coast cities, who didn’t have the power of the media pulpit or the money to influence Washington. Night after night, year after year, O’Reilly and “The Factor” hammered target after target, sometimes launched feud after feud. He insisted on common sense, decent, middle American values, and a strong military.

As a broadcaster, O’Reilly was without peer: He looked in the camera, lowered his chin, and began to talk, and once he began to talk, it was difficult to look away. O’Reilly and “The Factor” pioneered or embraced a range of program elements that magnified or emphasized his message, and were all so indelible that Stephen Colbert spent nearly a decade parodying them on Comedy Central.

There were dozens of elements, all memorable and like the messenger himself, came to symbolize an entire cable network: “Top Story,” “Factor Follow-Up,” “Pinheads and Patriots,” “Word of the Day” and “Factor Mail,” which dutifully offered both viewer praise and viewer criticisms. (Because O’Reilly always had the last word, he’d always have something to say about that, too). “Talking Points Memo” was a “Factor” masterpiece, and a deceptively simply one — a scroll of the words O’Reilly was saying off screen.

As other pundits have noted in recent days, how will Fox begin to replace this utterly unique formula? Will it try — or simply segue to a brand-new show and brand-new personality?

Moreover, how will longtime viewers — many of whom have been along for this ride since the October 1996 launch of “The Factor” — react? For Fox News and 21st Century Fox, that may be the most sobering question of all.