In a sign of a major political shift in Prince George’s County, the outspoken leader of a minority bloc on the Board of Education was chosen Thursday night as vice chairman.

The move came as a striking change for a 14-member board reshaped by the elections in November.

Edward Burroughs III, 26, the board’s longest-serving member, was selected by board colleagues Thursday night in a decision confirmed by several district officials Friday. A formal announcement is expected Monday.

The move marks a new chapter for the board, where Burroughs was known as a vocal critic of the school system’s previous chief executive during a string of scandals. He was part of a bloc that drew attention to inflated graduation rates, large pay raises to executive staff and a nearly $800,000 contract payout to outgoing CEO Kevin M. Maxwell.

Now, Burroughs takes a leadership role beside Alvin Thornton, 70, a longtime college professor and education expert recently named board chairman by County Executive Angela D. Alsobrooks (D). Alsobrooks had said that she would let the board select its own vice chairman.

In an interview last week, Burroughs praised Thornton, whom he described as a voice of integrity and experience and “someone we would be honored to learn from and partner with in this work.” Burroughs declined to comment Friday evening, pending an official announcement.

David Murray, a close ally of Burroughs’s on the board, called the new vice chairman “the dean of the board” for his long tenure, having started when he was a 15-year-old student member. Burroughs has served more than a decade and has been elected as an adult three times.

“He’s been here the longest, and he’s dedicated his adult life to the board, really,” Murray said.

Burroughs, who works as coordinator of a juvenile diversion program for the state’s attorney’s office, and Murray are among five elected board members from the millennial generation. All are recent college graduates who attended county schools and say they are deeply connected to the system they grew up in.

Murray said Burroughs’s role will make a difference on issues ahead, including working to boost the district’s lowest-performing schools.

“It’s definitely validating for us as millennials, and for our caucus, and for all of our constituents who were probably feeling voiceless,” Murray said. “It puts us in a position to deliver results.”