In recent weeks, Tucker Carlson, the conservative Fox News host, has challenged the Black Lives Matter movement, dismissed demonstrators as “criminal mobs,” accused a Texas police chief of “sounding more like a therapist than a cop” and mocked a CNN children’s special about racism that featured Elmo, the “Sesame Street” puppet.

His comments have generated a harsh backlash. Critics have called Carlson’s on-air monologues incendiary and accused him of making racist remarks. Major advertisers, including The Walt Disney Co. and Sandals, the vacation resorts, have fled, requesting that Fox News remove their ads from Carlson’s 8 p.m. hour.

Viewers, however, are tuning in.

“Tucker Carlson Tonight” was seen by 4.2 million people Monday, making it the most-watched television program in the country that night, ahead of entertainment fare on the major networks. His show was the highest rated on Fox News last week, and he has pulled ahead of Sean Hannity, the network’s usual ratings leader, in total viewers for June.

Fox News’ stars, including Carlson, are no stranger to advertising boycotts and denunciations from the left. But at a moment of deep national turmoil, prompted by the police killing of George Floyd in Minneapolis last month, the response to Carlson offers another sign of the nation’s deep political divide. Major American brands have recoiled from his program — and celebrities like Padma Lakshmi have accused him of spreading “race-baiting filth” — even as many viewers remain enthusiastic.

Carlson, a conservative pundit who previously hosted shows on CNN and MSNBC, has seized on the high Nielsen numbers as a sign that his message — which warns about censorship from the left and depicts the country’s unrest as ominous and violent — is resonating.

“You are not alone,” Carlson told viewers Tuesday, noting that his Monday program had ranked first among “cable and broadcast news, entertainment and sports.”

“You may feel like you are,” he continued. “Suddenly, your opinions qualify as crimes. Dare to say what you think at work and you will be fired in the middle of a recession. Write what you think online and you will be silenced by the big tech companies.”

But his remarks have not sat easily with Carlson’s advertisers, including companies like Papa John’s, Poshmark, Angie’s List and office furniture brand Vari, all of which have distanced themselves from “Tucker Carlson Tonight.” T-Mobile announced its defection in a memorable Twitter post from Mike Sievert, the company’s chief executive, who wrote: “Bye-bye, Tucker Carlson!”

Today, fitness equipment company NordicTrack also said it would no longer advertise on Carlson’s program.

“The show has almost no big-name advertisers left right now,” Kara Alaimo, a public-relations expert who teaches at Hofstra University, said in an interview. “This is just not an issue you want to be on the wrong side of, if you’re a mainstream brand.”

Fox News has said brands removed from “Tucker Carlson Tonight” typically have their ads run on other programs, and the network retains the revenue. Fox News also earns a significant portion of its income from subscription fees paid by cable providers, rather than spending by individual advertisers.

Rupert Murdoch and his son Lachlan, who control Fox News, are usually reluctant to make changes at the network because of outside pressure. Last week, Carlson acknowledged his superiors’ support: “We work for one of the last brave companies in America, and they’re not intimidated. We’re grateful for that.”

Since demonstrations began, Carlson has adopted a hard-edge approach, encouraging President Donald Trump to be more harsh, not less, in cracking down on protesters. The ad boycott intensified after Carlson, on June 8, said the unrest “is definitely not about black lives, and remember that when they come for you.” (Fox News said the pronoun “they” referred to liberal leaders, not protesters.)

This week, Carlson criticized police officials in Fort Worth, Texas, for dropping charges for rioting. Police responded by saying that more serious criminal charges had not been dropped, but Carlson repeated his criticism, calling the department’s actions “shameful.”

Though he enjoys Fox News’ backing, Carlson, a longtime Washington resident, may be on the cusp of leaving his liberal-leaning hometown. He recently put his Washington home up for sale and has spent much of the quarantine at his houses in Florida and Maine. Through a spokeswoman, the host declined to comment about his plans.

On Wednesday, Carlson yielded the nightly ratings crown to Hannity, who attracted 4.5 million viewers for his telephone interview with Trump. Across all of television, Hannity enjoyed the largest audience. Carlson was in second place, not far behind.