The advocate who oversaw the growth of charter schools in the nation’s capital for much of the past decade announced Tuesday that he plans to step down in May from one of the most powerful education posts in the city.

Scott Pearson said that his decision to leave the post of executive director of the D.C. Public Charter School Board after more than seven years on the job was his and that, after a summer respite, he hopes to continue working in D.C. education.

The departure of Pearson, 57, occurs at a time of conflicting currents for what is widely known as the education reform movement. His supporters hail the District’s charter sector — which educates close to half of all D.C. public school students — as among the best in the country. But charter schools and the broader reform movement are facing increasing resistance nationwide.

The charter board, whose seven members are appointed by the D.C. mayor, will select Pearson’s replacement and said it would launch a national search in coming weeks.

“What I think we have done in D.C. is show what charter schools can achieve when they are done right. And that is not only what they can achieve for themselves, but for the city as a whole,” Pearson said in an interview. “Charter schools deserve some of the credit for the thriving conditions of our city right now.”

Pearson, who has a background in business, was one of many alumni of the Obama administration’s pro-charter Education Department who left the federal government and pushed for alternatives to traditional schools in jurisdictions across the country. The effort came at a time when charter schools were politically popular and the D.C. charter sector was rapidly expanding.

When Pearson started as executive director in 2012, the city had 98 charter schools — which are publicly funded and privately operated — educating about 31,000 students. The District now has 123 charter school campuses serving more than 43,000 students. Charters operate with more autonomy than traditional public schools.

Enrollment in the traditional public school system has grown, too, from 45,000 to 51,000 students since 2012.

One of Pearson’s first efforts was to work with city leaders to launch a common lottery that would make schools more accessible by creating a single application that families could use to apply to campuses in both sectors.

“The best way I would describe Scott is tough but fair,” said Mashea Ashton, who last year founded Digital Pioneers Academy, a D.C. charter school. “The charter board keeps the bar high for all kids, and it gives us something to work toward.”

But Pearson is leaving at a more precarious moment for charters.

The latest scores on standardized tests show the traditional D.C. public school system outperforming the city’s charter schools, although both sectors have shown slow improvements in recent years. Paul Kihn, the deputy mayor for education, unsuccessfully called on the charter board to stop opening new campuses this year. Kihn said that too many middle and high schools in the charter and traditional public school sectors already have too many student vacancies.

For the first time since D.C. charters were established in 1996, enrollment dropped in the sector this year after the closure of five low-performing or financially troubled campuses. Five new schools are set to open next fall.

Nationally, some Democratic presidential candidates have distanced themselves from their pro-charter and school choice backgrounds.

Pearson, who earns $218,653 a year, acknowledged in an interview Monday that the political tide has shifted but said he remains confident that D.C. students in both sectors are better served because of charter campuses and the work he has led.

“I came in with a lot of ideas and a lot of things that I wanted to get done because I thought that the charter sector would best be able to fulfill its aspirations if it was properly supervised and if the authorizer was doing its job well,” Pearson said in the interview. “It is unquestionably better now.”

Under his tenure, Pearson said, the board has held troubled charter schools more accountable, intervening when schools are performing poorly or are in financial peril. The staff at the charter school board — which grew from 25 to 45 since 2012 — revamped the framework by which the performance of charter schools is assessed.

Thirty-five schools closed in Pearson’s time leading the board — a sign, Pearson said, that the regulatory authority is ensuring that high-quality schools operate in the city.

But critics have argued that frequent school closures have been a source of instability for families and the city. Pearson said the board has grown more adept at finding new operators to run failing charter schools so that they can remain open.

Jennifer Ross, the founder of National Collegiate Preparatory Public Charter, said Pearson’s focus on data often misses the challenges that schools educating students in poverty experience. The charter board voted to close National Collegiate in January because it was low-performing. Leaders of the Southeast Washington school recently sued the charter board, asserting that the closure of National Collegiate was unjust.

“Not only are we educators. Many times we are the caregivers for students and their parents,” Ross said. “The city deserves someone who understands that data may not fit perfectly in a square.”

The board also has been accused by families and city officials of acting slowly — or being too hands-off — when dealing with safety and mismanagement at schools. Pearson defended the board, saying it has made great strides in these areas in recent years.

When Pearson started in the job, for example, the charter board did not require schools to conduct lead testing or have emergency response plans. It does now.

Still, the sector has faced backlash after safety incidents at two public charter schools — Monument Academy and Rocketship Rise Academy — in recent months.

“This is a relatively young movement. The whole idea of charter authorization did not even exist 25 years ago,” Pearson said. “This is something that is evolving, and we are getting better each year.”

D.C. Council member David Grosso (I-At Large), who chairs the D.C. Council’s education committee, said he and Pearson have clashed over legislation. The most prominent confrontation was over Grosso’s 2018 discipline bill that said schools could suspend or expel students only in extreme circumstances. Pearson unsuccessfully lobbied against the measure.

Despite high-profile disagreements, Grosso said Pearson worked with the council on other efforts, including bringing more nurses and mental-health workers to campuses.

“He is someone who comes at it from a principled stance,” Grosso said. “He will be missed.”

Pearson’s successor will have to contend with intensifying demands that the D.C. charter sector be more transparent with the public. In response, the charter board has published more education outcomes and school financial information online. The charter board’s monthly meetings are now streamed online, and they offer more opportunities for public comment.

But Pearson stops short of supporting legislation the D.C. Council is considering that would require individual charter schools to be subject to the city’s public-records laws.

Charter school board chair Rick Cruz said he wants the next executive director to continue Pearson’s accountability and ­data-driven work while successfully navigating the bumpy terrain of education politics.

Cruz identified a need for a greater focus on informing the public of the successes of charter schools and their students.

“The politics are complicated, and they are certainly more so than they were eight years ago,” Cruz said. “We want someone who can build upon all the things that have been accomplished over the last eight years but can manage the challenges going forward.”

Leaders of EmpowerEd DC — a teacher advocacy organization that has been pushing for greater transparency in the charter sector — said they hope Pearson’s replacement is a “career educator” who listens to public feedback.

Pearson, who has two children in college, said he has no plans to leave the District.

“This is personal for me,” he said. “It’s my life’s work, and so I am certain I will stay involved.”