The chair of a Dorchester charter school's board has resigned after state investigations of a controversial, six-figure payout to an outgoing administrator.

Kevin A. Tarpley, a former Somerville alderman, had been board chairman of the Helen Y. Davis Leadership Academy since 2010. His departure, effective this month, was announced in a brief letter released at the board's meeting Tuesday night. Tarpley was not present.

"It has been a pleasure serving the students, families and the entire staff of the Academy as a member of the Board for the past 9 years," Tarpley wrote. "I wish each and every one of you success moving forward."

The board unanimously accepted Tarpley's resignation. He had exceeded the board's own term limits of four consecutive years for officers, according to a state auditor's report.

Reached Wednesday in Ohio, where he now resides, Tarpley said he voluntarily left before the May 2019 conclusion of his term in the “interest of protecting the academy.” Tarpley said he originally planned to transition out of leadership gradually, but his departure means the school “no longer [has] a lightning rod in which the powers that be at the department could use against the academy.” He referred to the state's Department of Elementary and Secondary Education.

Michael Silas, a cybersecurity engineer who joined the board last September, was elected as the new chair on a unanimous vote.

Tarpley's exit follows a pair of reviews last year — one by the state inspector general and another by the auditor — requested by the state's Department of Secondary and Elementary Education, known to insiders as DESE. Both investigations concluded that the school's board made excessive and, in some cases, unallowable payments in 2017 to Karmala Sherwood, the school's former executive director.

In the case of the state auditor's investigation, the school board admitted Sherwood's compensation package was "atypical" but pushed back against the agency's findings. In a response incorporated into the auditor's report, the school argued that the $380,000 compensation package was reasonable given her length of service, dual role as an academic leader and administrator, and "years of successful leadership" of Davis Academy. She was hired in 2003 as an instructional leader and promoted to principal and executive director in 2006.

Tarpley maintained that expenditure was lawful and dismissed the pair of investigations as an attempt to sully the school's public image.

“They are trying to paint a picture that this board was out of control, didn’t know what it was doing, and wasn’t run professionally,” he said. “It’s so believable because it's black folks,” he said, pointing to the school's predominately African-American board.

“I’m very confident the board acted within its rights and within the laws outlined by the state,” he continued. “That’s why the inspector general’s report said the board acted in good faith.”

State law details the obligations of boards of trustees of charter schools. Those duties include creating a strategic vision, holding school leaders accountable for academic success and providing financial oversight.

Silas, the new chair, said he plans to make fiscal stewardship a priority during his tenure.

"We're going to make more responsible decisions and we're going to comply with DESE" rules, Silas told WGBH News after the meeting. "I know certain things weren't done in accordance before. In my leadership, those things will be paramount."

The board is considering adding another board member named Sidney Salvodon. Following the meeting, board officials of the publicly-funded charter school declined to provide WGBH News copies of the potential member's resume and letter.

Located in the Fields Corner section of Dorchester, the Davis Academy was established in 2003. The grade 6-8 school operates on an annual budget of more than $3 million. For the 2017-2018 academic year, its student body was 86 percent African-American and 19 percent Hispanic. Almost 30 percent of students received special education services.

In the most recent review of its request to renew its state charter, the school was placed on probation, ordered to establish an escrow account and given a Dec. 2019 deadline to demonstrate "sustained academic improvement" in math, English and science.

According to the school's website, its mission is "to develop high achieving students of good character who use problem-solving, communication and interpersonal skills to inspire others and to catalyze educational, economic and political advancement within their communities and the broader nation."