Robert E. Primus, the first Black board chairman of the federal regulator responsible for approving railroad mergers, at first thought there was something wrong with his work phone. When he couldn’t unlock it he switched to his personal phone, only to learn that President Trump had fired him by email, effective immediately.

“I didn’t see it coming at all,” Mr. Primus, a Democrat, said in a recent interview. In January, the Trump administration had put a Republican in his place as the chairman of the Surface Transportation Board, which Mr. Primus saw as the president’s prerogative. But he had been appointed to the independent board by Mr. Trump in his first term and expected to remain on it, as had been the longstanding practice.

Instead, he heard a White House spokesman say the day after his firing in August that he did not “align” with the president’s agenda. Mr. Primus, a longtime congressional staff member and former lobbyist on transportation and national security matters, was reminded, he said, of Mr. Trump’s widely condemned comment during the 2024 campaign that immigrants were taking “Black jobs.”

“Maybe he felt that this job was not intended for Blacks," said Mr. Primus, 55. He acknowledged he was speculating, he said, but “it’s legitimate speculation. Because if you look across the board, there is a pattern.”

Mr. Primus is part of a series of firings of Black officials from high-profile positions in an overwhelmingly white administration that has banished all diversity, equity and inclusion programs across the federal government. And while there are no statistics on firings by race, an examination of the people Mr. Trump is appointing to fill those and other jobs shows a stark trend.

Of the president’s 98 Senate-confirmed appointees to the administration’s most senior leadership roles in its first 200 days, ending on Aug. 7, only two, or 2 percent — Scott Turner, the secretary of Housing and Urban Development, and Earl G. Matthews, the Defense Department’s general counsel — are Black.

The statistics were compiled for the Brookings Institution by Kathryn Dunn Tenpas, a senior fellow at the University of Virginia’s Miller Center who specializes in presidential personnel. The statistics track appointments to the 15 cabinet departments in the presidential line of succession: Treasury, Defense, Justice, Homeland Security, Interior, Agriculture, Commerce, Labor, Energy, Health and Human Services, Transportation, Housing and Urban Development and Veterans Affairs.

“Trump seemed to be very proud to have ‘Blacks for Trump’ at all of his rallies and behind the podium, but not behind him in the cabinet meetings,” said Dedrick Asante-Muhammad, the president of the Joint Center for Political and Economic Studies, a think tank that tracks Black representation in government leadership, among other markers. The dearth of Black people at the top, he said, would result in “radical substantive policy changes” for African Americans.

“When we’re not in the room,” he said, “things don’t tend to go better for us.”

Mr. Trump’s highest-profile firing of a senior Black leader was in February, when he ousted Gen. Charles Q. Brown Jr., the second Black chairman of the Joint Chiefs of Staff and the nation’s senior military official. Joint Chiefs chairmen traditionally remain in place as administrations change, regardless of the president’s party, and in 2020 Mr. Trump had nominated General Brown, a fighter pilot, to be the Air Force’s chief of staff. But Defense Secretary Pete Hegseth had previously said that General Brown should be fired because of a “woke” focus on D.E.I. programs in the military and questioned whether he was promoted because of his race.

General Brown was replaced with a little-known Air Force general, Dan Caine.

The president has fired other Black officials, like Mr. Primus, from top jobs at government agencies and independent boards that typically serve multiple administrations.

Those terminated include Carla Hayden, the first African-American and the first woman to be the librarian of Congress; Gwynne A. Wilcox, the first Black woman to serve as a member of the National Labor Relations Board; and Alvin Brown, the only Black member of the National Transportation Safety Board at the time of his removal.

Willie L. Phillips, the first Black person to be the chairman of the Federal Energy Regulatory Commission, stepped down from his position in April at the request of the White House. The president has since nominated David LaCerte to replace him.

Mr. Trump has tried to fire Lisa Cook, the first Black woman to serve on the Fed’s board of governors, but she has sued to stop him. Last week, the Supreme Court declined to allow Mr. Trump to immediately remove her and said it would review his efforts to oust her at oral arguments in January.

Mr. Primus, Mr. Brown and Ms. Wilcox have also filed lawsuits asking to be reinstated.

General Brown, Dr. Hayden and Mr. Phillips have been replaced by white men. A white man has been nominated to replace Mr. Brown, and two white men have been nominated to fill seats on the labor relations board after Ms. Wilcox was fired. Mr. Primus and Ms. Cook have not yet been replaced.

“You don’t need a very sophisticated analysis to read into what this means,” said Cathy Albisa, the former vice president at Race Forward, a nonprofit that promotes racial equity in government. Ms. Albisa now runs an organization, Branch4, supporting federal workers. “It is a resegregation of the work force, and an attack on the Black middle class.”

In the first Trump administration, there were fewer high-profile firings of Black workers. But there was only one Black official — Ben Carson, the housing secretary — among the 70 Senate-confirmed nominees to the major government departments in the first 200 days. (Dr. Carson returned to the administration last month as an adviser to the Agriculture Department.)

In the same 200-day period for previous presidents, according to Brookings, Black officials accounted for 21 percent of Senate-confirmed nominees under President Joseph R. Biden Jr., 13 percent under President Barack Obama and 8 percent under President George W. Bush.

Black Americans make up about 14 percent of the U.S. population.

A White House spokesman, Kush Desai, rejected criticism that Mr. Trump was undermining Black Americans. But he did not address the lack of diversity in appointments.

“President Trump pledged to build a government and economy that works for every American, and the administration is hard at work restoring the historic private-sector job, wage and economic growth that Americans, including Black Americans, enjoyed during his first term,” Mr. Desai said.

‘I Had to Fight This’

Mr. Trump informed Ms. Wilcox in a late-night email on Jan. 27 that she was being removed from her position on the labor relations board, effective immediately. No cause was given. It was the beginning of the administration’s test of the boundaries of the president’s power over independent agencies.

Ms. Wilcox, a Democrat and former union lawyer, was the first board member in its 90-year history to be removed by a president. A week before, in the very first hours of his administration, Mr. Trump had signed an executive order calling for an end to D.E.I. programs and the “termination of all discriminatory programs” in the government, including in federal employment practices.

“We had targets on our backs, no doubt about it, by virtue of the color of our skin,” Ms. Wilcox, 72, said in an interview. “But I did not get this job because of D.E.I. I got it because of my experience.”

Since then, she has fought her firing, calling it “unlawful and unprecedented.” In April, the Supreme Court ruled that Mr. Trump could temporarily remove her while her challenge goes forward.

Ms. Wilcox was nominated to the board, which enforces laws protecting workers’ rights, in 2021 and 2023 by Mr. Biden, and she was confirmed twice by the Senate. Her second term was to end in August 2028.

As the first Black woman to serve on the labor relations board since its creation in 1935, “I didn’t get overwhelmed by the thought of it,” she said. Instead, “I embraced it.’’

At the time she was nominated, Ms. Wilcox was a senior partner at a labor law and employment law firm in New York. She had spent her career championing the rights of a diverse group of workers, starting in a legal services office where she represented young white women in domestic violence cases. Her clients inspired her to practice labor law, she said, a career she started in a regional office of the N.L.R.B.

Ms. Wilcox said she was not thinking about breaking racial barriers when she accepted the appointment, nor did race play a role in how she decided cases. “I made decisions based upon my application of the National Labor Relations Act to the facts presented in each case assigned,” she said.

She worried about the work that has halted as a result of her removal. Only one board member remains, and without a quorum of three, the board cannot resolve cases. American workers who are awaiting decisions on issues like reinstatements and back pay after being unlawfully terminated, suspended or laid off have had their lives hanging in the balance.

“I don’t know what the Supreme Court will decide,” Ms. Wilcox said. “But I had to fight this. Not just for me, but for working people, including those who have cases before the N.L.R.B., and to fight for the agency.”

Black workers, particularly Black women, have been hard hit by reductions in the federal work force overall. According to a New York Times tracker of Mr. Trump’s cuts, agencies where racial minorities and women were a majority of the work force, such as the Education Department and the U.S. Agency for International Development, were targeted for the largest work force reductions or complete elimination. Black women made up nearly a quarter of the work force in agencies such as the Internal Revenue Service, which also saw deep reductions, according to a Times analysis.

Frederick Gooding Jr., a historian and professor of African American studies at Texas Christian University and the author of “American Dream Deferred: Black Federal Workers in Washington, D.C., 1941-1981,” said that the federal government was one of the first integrated workplaces in the country. It quickly became a ladder to the middle class for Black Americans who now have a disproportionately large presence in parts of the work force.

“When we look at Black people in this country, their relationship with the federal government provides a window into this thing called the American dream,” Dr. Gooding said. “What is happening right now is shameful.”

‘Thank You for Your Service’

Dr. Hayden did not see her firing coming, either.

The librarian of Congress, who was appointed a decade ago by Mr. Obama as the 14th person in the role since its creation in 1802, was at her mother’s home in Baltimore on a Thursday evening in May.

“I was there a little early, like 6:30,” she told the author and producer Kwame Alexander in a conversation onstage at the annual convention of the American Library Association in June. “So a little happy hour. You know, TV’s on in her den, and I’m looking at the phones and stuff. And I see this text.”

Dr. Hayden, 73, who is now a senior fellow at the Andrew W. Mellon Foundation, declined to be interviewed by The New York Times. But she spoke openly about her firing at the library association convention.

The text message, she told Mr. Alexander and the crowd, was two sentences, addressed casually to “Carla,” from someone she had never heard of. “On behalf of President Donald J. Trump, I am writing to inform you that your position as the Librarian of Congress is terminated effective immediately,” read the text from Trent M. Morse, the deputy director of White House personnel. “Thank you for your service.”

“I turned to my mom and said, ‘This is weird,’” Dr. Hayden told Mr. Alexander. At first she thought it wasn’t real, Dr. Hayden said, then turned to address the crowd.

“I’m among friends, right?” she said. (Dr. Hayden, who was the chief librarian in Baltimore for more than two decades, served as the library association’s president in 2003 and 2004.) She lowered her voice to a dramatic stage whisper.

“I’ve never been fired before,” she said.

Mr. Trump has appointed Todd Blanche, the deputy attorney general and his former lawyer, as the acting librarian of Congress.

The day after Dr. Hayden’s ouster, she learned from a briefing by the White House press secretary, Karoline Leavitt, that her dismissal was the result of unspecified “concerning things that she had done at the Library of Congress in the pursuit of D.E.I.,” including allowing “inappropriate books in the library for children.”

The Library of Congress, the largest library in the world, is the main research arm of Congress and also provides scholars access to its vast collections of presidential papers, manuscripts, films, maps, letters and photographs. It does not lend books to children or adults.

“I must say,” Dr. Hayden said wryly of Ms. Leavitt’s remark, “it has been interesting.”

Kitty Bennett contributed research.