In light of the sexual-harassment allegations made against O'Reilly - the same thing that led to Ailes's ouster last summer - 21st Century Fox Inc., the network's parent company, announced the 67-year-old host's departure on Wednesday afternoon.
In an internal memo sent to 21st Century Fox employees that has been shared by U.S. media, the company writes the decision was made after "extensive review done in collaboration with outside counsel".
Mr. O'Reilly has denied any wrongdoing, saying he paid settlements to "put to rest any controversies to spare my children".
O'Reilly has been an anchor at Fox News since he started at the network in 1996 and his show, The O'Reilly Factor, is the channel's top-rated programme, bringing in $147m (£188m) in advertising revenue in 2016, according to ad-tracking firm Kantar Media.
The embattled primetime host is widely disliked at Fox News and its parent company 21st Century Fox, both feared and loathed for his outsized ego and rude temperament, according to six current and former high-ranking sources at the company. Fox confirmed on Wednesday that O'Reilly will not return to the network.
People upset about O'Reilly's forced departure may quit their cable subscriptions, and Fox News would lose out on those fees, DiClemente said.
"NOW is calling for a thorough, independent investigation by New York City and State authorities into the culture of sexual and racial harassment at Fox News, and for appropriate accountability measures to be taken", said O'Neill. Sean Hannity's FOX News show, "Hannity", will stay in the 10pm EST/ 9pm CST timeslot.
Lastly, and most importantly, we want to underscore our consistent commitment to fostering a work environment built on the values of trust and respect.
The O'Reilly Factor averaged 3.98 million viewers per episode during the first quarter of 2017, the most of any prime-time cable news show, and "the consensus in the TV news industry is that losing O'Reilly's program...could drive down ratings for the entire Fox News prime-time line-up", notes The Los Angeles Times.
"O'Reilly, who had hosted "The O'Reilly Factor" on Fox since 2001, praised his company and loyal viewers for their support". While Fox's two biggest rivals, CNN and MSNBC, would not be interested in hiring him, conservative upstarts like Newsmax or One America News (OANN) could be.
O'Reilly's public statement on Wednesday gave no indication about what he might do next.
"They could literally go dark during the time his program airs and they would still be profitable", said Wieser.
O'Reilly is also one of the country's most popular nonfiction authors.