Tommy Chang, the embattled superintendent of Boston Public Schools, is resigning.

In a statement, Chang said that he is, "in active negotiations with the Boston School Committee for a mutual parting of ways."

Chang was hired three years ago after a national search. He came from Los Angeles public schools, where he ran a learning innovation center. Boston was Chang's first job running an entire school district.

The Boston Teachers Union issued a statement saying it "enjoyed a collaborative relationship" with Chang.

"He showed a clear commitment to elevating important conversations about race and equity, and it was clear he cared deeply about the students we serve," the statement continued. "We wish him all the best in his future endeavors."

In the last year, he came under fire for a controversial plan to change school start times and an Internal Revenue Service audit, which found the district had used student activity funds to make under-the-table payments to employees. Boston had to pay $28,000 in fines and back taxes.

Last December, Chang reversed a decision that would have shifted high school start times to later in the morning. The idea was based on research that shows more sleep for teens can lead to better performance and higher test scores. But to keep transportation costs down, the district would have also needed to make younger students start and end their school days earlier. The move caused an uproar among parents who protested the financial burden the change would put on families.