In the wake of George Floyd’s murder in May 2020, protests, looting, and anger were boiling up in the streets of Boston, a city that has played host to both abolitionists and vicious race riots. At Boston University, Black students demanded action to address campus racism.

The university had a dramatic response. It announced a few days later that it had recruited Ibram X. Kendi, the celebrity professor who had spawned a movement through his book, “How to Be an Antiracist.”

The plans were ambitious. Dr. Kendi would head up a new Center for Antiracist Research. The university would develop undergraduate and graduate degrees in antiracism. Within months, millions had poured in for a center whose mission, Dr. Kendi said, would be to “solve seemingly intractable problems of racial inequity and injustice.”

Now, a mere three years later, the center is being downsized. More than half of its 36 employees were abruptly told last week they were being laid off. The center’s budget is also being trimmed in half. The planned degree programs have not come to fruition. And the center’s news site called “The Emancipator” is no longer a partnership with The Boston Globe.

The reorganization is partly a sign of the times. Enthusiasm for funding racial justice causes has diminished as Mr. Floyd’s murder has faded out of the media spotlight and conservatives direct their ire toward efforts to diversify companies and institutions and to teach race in schools.

But the center’s struggles come amid deeper concerns about its management and focus, and questions about whether Dr. Kendi — whose fame has brought him new projects from an ESPN series to children’s books about racist ideas in America — was providing the leadership the newly created institute needed. Until the university established the center, the 41-year-old Dr. Kendi had never run an organization anywhere near its size.

On Wednesday, Boston University announced it was conducting an inquiry into complaints from staff members, which include questions about the center’s management culture and the faculty and staff’s experience with it, as well as its grant management practices.

Dr. Kendi said in an interview that he made “the painful decision” to reduce the program’s size and mission in an effort to guarantee its future, even though the center is currently financially healthy. The university said Friday that the center has raised nearly $55 million and its endowment contains about $30 million, with an additional $17.5 million held in reserves.

The bulk of the donations came from pledges made during the first year, and the university reported $5.4 million in cash and pledge payments in the most recent fiscal year.

Despite the university’s statement that it would look into the center’s management, the university’s interim president, Kenneth Freeman, on Thursday voiced strong support for Dr. Kendi, saying the professor had come to the university early in the summer with his idea for the reorganized center.

“We continue to have confidence in Dr. Kendi’s vision and we support it,” Mr. Freeman said.

But several former staff and faculty members, expressing anger and bitterness, said the cause of the center’s problems were unrealistic expectations fueled by the rapid infusion of money, initial excitement, and pressure to produce too much, too fast, even as there were hiring delays due to the pandemic. Others blamed Dr. Kendi, himself, for what they described as an imperious leadership style. And they questioned both the center’s stewardship of grants and its productivity.

“Commensurate to the amount of cash and donations taken in, the outputs were minuscule,” said Saida U. Grundy, a Boston University sociology professor and feminist scholar who was once affiliated with the center.

The turmoil comes as Dr. Kendi’s work continues to face attacks from the outside. In his books he contends that there’s no middle ground on race — everyone is either racist or actively antiracist. And he suggests that all disparities in Black outcomes and achievements are because of racism. That has ignited criticism from conservatives, ranging from some Black intellectuals to Republican-led state governments, which have banned his books from their classrooms and libraries.

Dr. Kendi acknowledged that the fund-raising environment for the center “isn’t like it was in 2020 when it was the popular thing to do.” But he added that the center still has committed funders.

And calling the changes in the center a “major pivot,” he said, “I really had to ensure that 20 years from now, 50 years from now, 100 years from now, the center will be around.”

The center’s new model, Dr. Kendi said, will be the first of its kind, a fellowship program for antiracist intellectuals who will be in residence at the university for nine months, participating in public events while conducting their own research.

Dr. Kendi was a professor at the University of Florida in 2016 when his book, “Stamped From the Beginning,” a history of racist thought in America, was a surprise National Book Award winner. A subsequent book, “How to Be an Antiracist,” became a best seller in 2019.

As much a public influencer as a scholar, Dr. Kendi became a flashpoint in the culture wars with his idea that to be an antiracist, one must first acknowledge being a racist.

Dr. Kendi came to Boston at both an opportune time — in the middle of the 2020 racial reckoning — and a challenging one — the early months of the Covid pandemic.

Acknowledging a difficult start-up in the midst of the pandemic — along with some conflicts among staff members who had strong and divergent ideas for the center’s focus — Dr. Kendi said he was proud of the center’s work so far.

The center says its key initiatives and accomplishments include The Emancipator; its National Antiracist Book Festivals; policy conferences on bigotry and racial classifications; 10 amicus briefs filed in racial-justice lawsuits and an antiracist technology initiative.

Even as the cutbacks were announced, the center was preparing this weekend for a meeting of 60 journalists who cover race. From the outside, though, the center’s operations appeared to be struggling. Portions of its website had been taken down.

And the center’s work, perhaps inevitably, has become synonymous with the celebrity and notoriety of Dr. Kendi.

Even as he was overseeing the center, along with a staff of administrators and academics that at one point totaled about 43 people, his business franchise has continued to grow. And some worry he has taken on far more work than can be done while running the center.

In publishing, he has spun off children’s books based on his theme. “Antiracist Baby” is geared to young children, and “How to Be a Young Antiracist,” is aimed at 12- to 17-year-olds. He has also published a guide for parents, “How to Raise an Antiracist.” His other children’s books include adaptations of work by Zora Neale Hurston. He is a contributor to The Atlantic.

In broadcasting, he has hosted his own podcast while also appearing as a commentator on CBS and cable television. He has formed his own production company, Maroon Visions, recently involved in an ESPN+ series exploring racism in sports, “Skin in the Game, which premiered on Wednesday.

He teaches an undergraduate course at B.U. on antiracism and frequently speaks at universities and conferences across the country, sometimes drawing controversy.

Dr. Grundy said that despite Dr. Kendi’s busy outside schedule, “Ibram didn’t want to give up any power.”

And in academia, where popular success can often generate pushback, his work has been criticized by some scholars who question its academic rigor and also by some on the left who worry that it has been influenced, to some degree, by the big donors who have helped create the center.

Spencer Piston, a professor of political science who worked in the center’s policy office, criticized the university’s original decision to bring in Dr. Kendi, which he viewed as a substitute for addressing more specific student complaints — including criticism of the campus police force and the lack of faculty diversity.

“It’s a failure of a particular type of corporatist university response to those same struggles,” Dr. Piston said.

Within the first year following Dr. Kendi’s hiring, more than $43 million in grant and gift pledges had flowed in, including an anonymous $25 million gift and $10 million from Jack Dorsey, co-founder of Twitter.

Money was streaming in, but the new staff came on board slowly as the fledgling operation attempted to work remotely.

More than one former employee complained about how grants were handled, with their allegations including conflicts of interest or misleading promises to donors. The center’s staff also became engaged in a political struggle, of sorts — a debate over what antiracism should look like.

Dr. Piston, for example, questioned whether the center hewed to donor interests at the expense of interacting with community-based groups. He cited the participation of the chief executive of Vertex Pharmaceuticals, which is developing a treatment for sickle cell anemia, in a center conference on public health. The company’s foundation is a donor.

Phillipe Copeland, a professor in the university’s Department of Social Work who also served at the center until he resigned in June, said some faculty had chafed at Dr. Kendi, making Dr. Copeland’s work — developing the graduate program in antiracism studies — difficult.

”There were some bad feelings about interactions people had with Dr. Kendi that made some people not want to participate and support what we were doing,” Dr. Copeland said. “I heard that a lot.”

In an interview, Dr. Kendi said that critics were using the situation “to settle old scores and demonstrate that I’m a problem or that antiracism is a problem.”

“Unfortunately we live in such a polarized, spiteful sort of reactionary moment,” he said.

Colbi Edmonds contributed reporting.