In the briefing room, Mr. Ateba joined a class of reporters who are allowed on the premises but don’t have permanent seats, often jockeying for back-row seats that stay empty when other journalists don’t show up. These reporters are rarely called upon during briefings. (Mr. Ateba currently has a “hard pass,” which confers regular access to White House grounds. In May, the White House announced that it was tightening requirements for the credential — a move that Mr. Ateba and others in the media saw as a response to his behavior.)

Mr. Ateba grew frustrated that he didn’t get to ask a question during the first months of the Biden administration, he said, and he asked to meet privately with Ms. Psaki. (Ms. Psaki did not comment for this story.) After the meeting, which Mr. Ateba recalled as being cordial, Ms. Psaki did call on him during a briefing, on Sept. 1, 2021. Mr. Ateba asked a friendly question about whether Mr. Biden’s detractors should apologize for calling him “sleepy.”

What followed, Mr. Ateba said, were several amicable months.

Then, in November 2021, the Biden administration banned travelers from eight southern African nations from traveling to the United States over fears of the newly identified Omicron variant of the coronavirus. The move drew criticism from public health experts, who said it was unsupported by science and appeared to scapegoat Africa, as the variant was already known to be spreading widely in Asia and Europe. In press briefings soon after, Mr. Ateba asked Dr. Anthony Fauci, and later in a combative exchange with Ms. Psaki, about the ban, which he called “racist.”

“You know that’s false,” Mr. Ateba said, accusing Ms. Psaki of inflating the number of cases in South Africa.

“It’s not effective to scream over your colleagues in here,” Ms. Psaki said.

Ms. Psaki and Mr. Ateba met privately again. As their briefing room exchange made the rounds on Twitter, Fox News invited Mr. Ateba to appear on “Tucker Carlson Tonight.”

“I wondered, is it in my best interest?” Mr. Ateba recalled. “Do I want to do this? Is anyone trying to use me?” Ultimately, he concluded that “the condescension was too much, ” and that it seemed to him that Ms. Psaki was happy to entertain his questions when they were deemed friendly, but quick to dismiss him when he asked a tough question that was squarely on his beat. He went on the air. On Dec. 3, he told the fill-in host, Jesse Watters, that if Mr. Trump had passed a travel ban only against African countries, he would have been excoriated as racist.