In early June 2020, Mr. Carlson told his audience that the Black Lives Matter protests were “definitely not about Black lives” and to “remember that when they come for you.” The next evening, as Fox’s public relations team insisted Mr. Carlson’s comment was being mischaracterized, Mr. Carlson leaned in. “The mob came for us — irony of ironies,” he told Fox viewers. “They spent the last 24 hours trying to force the show off the air for good. They won’t succeed in that, thankfully. We work for one of the last brave companies in America, and they’re not intimidated.”

Off-camera, Mr. Carlson could be less defiant. In a conversation that spring with Eric Owens, one of his former employees at The Daily Caller, he worried that the controversy over his show had made it difficult for his children to get jobs and internships; he worried that his younger children wouldn’t get into college. “It’s not right for this to affect my family, and literally affect my children’s future,” Mr. Carlson said, according to Mr. Owens.

But it’s less clear whether the attacks significantly affected Fox’s bottom line: To compensate for the lost advertising, Fox turned “Tucker Carlson Tonight” into a promotional engine for the network itself. It replaced the fleeing sponsors with a torrent of in-house promos, leveraging Mr. Carlson’s popularity to drive viewers to other, more advertiser-friendly offerings. By early 2019, roughly a fifth of all advertising “impressions” on the show were from in-house ads, according to data from the analytics company iSpot.tv. That summer, as Fox fended off criticism of Mr. Carlson’s “hoax” comments, the proportion climbed to more than a third. (A Fox spokeswoman said the actual proportions were lower, but declined to provide specific figures.) “Fox is basically an enormous loyalty brand,” said Jason Damata, the chief executive officer of Fabric Media, a media consultancy. “He’s the hook.”

Other advertising slots were taken by direct-to-consumer brands that either didn’t care about Mr. Carlson’s bad publicity or saw that they could use his intensity to sell their products. Beginning in January 2019, MyPillow, a Fox advertiser whose chief executive, Mike Lindell, is a major promoter of Mr. Trump’s stolen-election lie, began airing more than $1 million worth of ads on “Tucker Carlson Tonight” each month. Fox appeared to be using MyPillow to cushion Mr. Carlson: As other advertising dried up, the company’s ads spiked. (All told, through December 2021, Mr. Lindell had bought advertising that would have cost $91 million at publicized rates; discounts probably made that sum lower.)

Blue-chip advertisers would never return to the show in force. But thanks in part to the large audiences he could provide for those advertisers who remained, and the premium prices Fox could charge them, Mr. Carlson’s ad revenue began to recover. Every year since 2018, “Tucker Carlson Tonight” has brought more annual ad revenue to Fox than any other show, according to estimates by iSpot. Last May, after promoting the white supremacist “replacement” theory, Mr. Carlson had half as many advertisers as in December 2018 but brought in almost twice as much money.

As “Tucker Carlson Tonight” became more toxic to advertisers, it also began featuring fewer guests who disagreed with the host, and more guests who simply echoed or amplified Mr. Carlson’s own message. It wasn’t just that liberals didn’t want to debate him, though some now refused to appear on the show, as Mr. Carlson complained during a Fox appearance last summer; Fox was learning that its audience didn’t necessarily like hearing from the other side. “From my discussions with Fox News bookers, my takeaway is that they’ve made the judgment that they just don’t do debate segments anymore,” said Richard Goodstein, a Democratic lobbyist and campaign adviser who appeared regularly on Mr. Carlson’s show until the summer of 2020. Across much of the Fox lineup, former employees said, producers were relying more and more on panels of pro-Trump conservatives competing to see who could denounce Democrats more fervently — a ratings gambit one former Fox employee called “rage inflation.” (One exception, perhaps, is “The Five,” a panel show featuring four conservative co-hosts and one rotating co-host from the left, which has beaten Mr. Carlson in total viewers in some recent months.)

And as advertisers fled, Mr. Carlson’s opening monologue grew. Where once he spoke for only a few minutes, sometimes in a neutral just-asking-questions mode, he now often opened the show with a lengthy stemwinder, addressing his audience as “you” and the objects of his fury as a shadowy “they.” Ratings data showed that the monologues were a hit with viewers, according to one former and one current Fox employee, and by 2020, Mr. Carlson regularly spoke directly to the camera for more than quarter of the hourlong show. Instead of less Tucker, the audience got more.