NPR has suspended Uri Berliner, the senior business editor who broke ranks and published an essay arguing that the nonprofit radio network had allowed liberal bias to affect its coverage.

Mr. Berliner was suspended by the network for five days, starting Friday, for violating the network’s policy against doing work outside the organization without first getting permission.

Mr. Berliner acknowledged his suspension in an interview with NPR on Monday, providing one of the network’s reporters with a copy of the written rebuke. In presenting the warning, NPR said Mr. Berliner had failed to clear his work for outside outlets, adding that he would be fired if he violated the policy again.

Mr. Berliner’s essay was published last week in The Free Press, a popular Substack publication.

He declined to comment about the suspension. NPR said it did not comment on personnel matters.

The revelation of Mr. Berliner’s punishment is the latest aftershock to rattle NPR since he published his essay. Employees at the public radio network were taken aback by Mr. Berliner’s public condemnation of the broadcaster, and several have said they no longer trust him because of his remarks. Mr. Berliner told The New York Times last week that he did not reach out to the network before publishing his essay.

After Mr. Berliner’s essay was published, NPR’s new chief executive, Katherine Maher, came under renewed scrutiny as conservative activists resurfaced a series of years-old social media posts criticizing former President Donald J. Trump and embracing progressive causes. One of the activists, Christopher Rufo, has pressured media organizations into covering controversies involving influential figures, such as the plagiarism allegations against Claudine Gay, the former Harvard president.

NPR said on Monday that Ms. Maher’s social media posts were written long before she was named chief executive of NPR, and that she was not working in the news industry at the time. NPR also said that while she managed the business side of the nonprofit, she was not involved in its editorial process. Ms. Maher said in a statement that “in America everyone is entitled to free speech as a private citizen.”

Several NPR employees have urged the network’s leaders to more forcefully renounce Mr. Berliner’s claims in his essay. Edith Chapin, NPR’s top editor, said in a statement last week that managers “strongly disagree with Uri’s assessment of the quality of our journalism,” adding that the network was “proud to stand behind” its work.

Some employees have begun to speak out. Tony Cavin, NPR’s managing editor for standards and practices, took issue with many of Mr. Berliner’s claims in an interview with The Times on Tuesday, saying Mr. Berliner’s essay mischaracterized NPR’s coverage of crucial stories.

Mr. Cavin said NPR’s coverage of Covid-19, one of the lines of reporting that Mr. Berliner criticized, was in step with reporting from other mainstream news organizations at the time. The coverage, he said, attributed the origins of the virus to a market in Wuhan, China. He also defended NPR’s coverage of Russian interference in the 2016 U.S. election, another area Mr. Berliner focused on, noting that Robert Mueller, the special counsel investigating the issue, concluded that Russian state actors had made attempts to sway the election.

Mr. Cavin also pointed out that NPR had no way to verify early articles about Hunter Biden’s laptop after the story broke but pursued follow-up stories examining the situation. Mr. Berliner wrote that NPR had “turned a blind eye” to the story about Mr. Biden’s laptop.

“To somehow think that we were driven by politics is both wrong and unfair,” Mr. Cavin said.