In a scathing report by the White House that accuses the Smithsonian of downplaying the role of the country’s founders while pursuing “extreme political activism,” the historian Anthea M. Hartig is mentioned nearly 230 times.

It says she spreads “radical activist ideology.”

It cites her recent comments to students about seeing history as a “prime tool of social justice.”

And it claims that the Smithsonian museum she leads has worked to “undermine faith in American institutions and the longstanding shared ideals of the American people.”

Ms. Hartig, who has been the director of the National Museum of American History since 2019, has commissioned exhibitions that go beyond highlighting the accomplishments of presidents. They document the lived experiences of ordinary people, sometimes focusing on race, sexuality and colonialism.

Her work seems to have infuriated the White House, whose Domestic Policy Council released the report on Saturday, the 250th anniversary of the nation’s founding. But many historians support her goal of telling a more nuanced story of the United States.

“At a time when American history and the historical profession are under attack,” said Erika Lee, a historian at Harvard University, “she has remained committed to preserving and sharing the fullest record of the American story — one that is full of nuance and contradictions.”

Born the same year that the National Museum of American History opened, in 1964, Ms. Hartig trained in California as a historian interested in the contributions of immigrants and Latino communities. She has degrees from the Los Angeles and Riverside campuses of the University of California, and in 2001 published her dissertation on the role of citrus growers in the development of Southern California. Then she spent most of her career working for nonprofits dedicated to preserving and teaching the history of the West Coast.

Scholars said her interest in social history made her an effective public historian because she was able to communicate with the Smithsonian’s diverse audiences.

“She really goes to bat for curators who are looking to tell stories that have not been platformed in our nation’s museums,” said Matthew J. Garcia, a historian at Dartmouth College who met Ms. Hartig when they were doctoral students. “By doing that, she has been wrongfully accused of being ideological.”

During President Trump’s second term, the White House has been critical of the Smithsonian, including the organization’s leader, Secretary Lonnie G. Bunch III. When the administration previously singled out the director of a Smithsonian museum — the president called Kim Sajet, the National Portrait Gallery’s director, a “strong supporter of DEI” — she resigned.

A White House spokesman did not respond to questions about whether Ms. Hartig should remain in her position. Ms. Hartig did not respond to requests for comment.

Many historians have come to her defense, however, arguing that the White House was using its own ideological lens to accuse the Smithsonian of being unpatriotic while presenting things out of context for shock value.

“Reports of this ilk reveal less about the museums they target than about the anxieties of their authors,” the Organization of American Historians, where Ms. Hartig previously served as president, wrote in a statement.

The White House’s report criticized Ms. Hartig for several exhibitions at the museum. They included the 2020 exhibition “Girlhood (It’s Complicated),” which had pages from a transgender child’s diary; the 2023 exhibition “Entertainment Nation,” which described Alexander Hamilton as “flawed,” in part because he owned slaves; and an initiative that had museum staff traveling to places including Mexico City to study the work of immigrant rights activists.

One video of Ms. Hartig speaking to students at U.C.L.A.’s Luskin Center for History and Policy was repeatedly cited as evidence of bias.

The report quoted her as telling the students that history was a “prime tool of social justice,” while omitting a later part of her speech where she describes historians as “seekers of truth” as well as “embracers of nuance, ambassadors of empathy and defenders of inalienable rights.”

The historian David Myers, who invited Ms. Hartig to speak to the U.C.L.A. students, said the White House had an outdated view of the profession. Public historians “want to open new interpretations of the past and not just present existing ones,” he explained. “History is a tool of civic engagement.”

When the museum opened, President Lyndon B. Johnson described it as a place to “illuminate our heritage so that others could see a little better our legacy.” It was quickly swept into the history of its own era during the civil rights movement, and it eventually created a division that collected materials to elevate the role that underrepresented groups played in American history.

John Gray, the museum’s previous director, said the institution had maintained its approach under Ms. Hartig.

“The purpose of the National Museum of American History is to provide us with a common reference to our history and the parts of our history that bring us together, and it does that beautifully,” he said. “Attacking an individual in the name of politics, or in the name of history, is not a viable way to understand America.”