Superintendent Tommy Chang is parting ways with Boston Public Schools after serving out just three years of his five-year contract.

Chang presided over a number of controversies at Boston Public Schools, including a botched roll-out of earlier start times, an audit from the Internal Revenue Service, and, most recently, a lawsuit over the school district's refusal to disclose how often they share student information with federal immigration authorities.

Paul Reville, professor at the Harvard Graduate School of Education and former state Secretary of Education, said Chang was not successful in forging political alliances with his boss, Mayor Marty Walsh, and the BPS community more broadly.

"It's partly his failing, it's partly a system failing," Reville said. "I think there was a significant lack of alignment between the mayor, the School Committee, and the superintendent in terms of what were the priorities for the school system, what was the strategic agenda for improvement of the Boston Public Schools, and then, of course, how ... you communicate that to the community and get the community engaged in supporting the strategic direction of the school system."

"I don't think they were ever really on the same page in some sense, nor do I think the superintendent connected very well with the mayor's office, with the School Committee or with the community as a whole," he added.

Reville said the failure to make those connections left Chang vulnerable when controversies bubbled up.

"What seemed to be to be the case was Tommy Chang was more vulnerable to day-to-day crises that emerge in the tenure of any urban superintendent because he didn't have the clear support of the mayor, and because he hadn't connected well and developed his own political network within the community," Reville said.

"He was vulnerable in ways we hadn't seen in the past," he continued.