PORTLAND — Maine’s largest school district has made progress since Jim Morse became superintendent two years ago, but the person who replaces him will still have a lot of work to do, according to Morse and other school officials.

The superintendent announced Thursday that he will retire when his three-year contract runs out at the end of June. He has been an educator for 25 years.

Morse, 57, the former superintendent of RSU 18 in Oakland, took the job as head of the city’s public schools in July 2009, following a financial crisis that prompted the resignation of a superintendent and a business manager.

Morse said he had no idea how “broken” the school district was when he became superintendent, but he has done the “hard work of transformation” that will enable the district to excel under his successor.

“I’ve made the changes necessary to make this a high-performing district,” Morse said. “There’s still a lot of work to do, but now you have the infrastructure to build success.”

Morse informed the school board Tuesday, during an executive session, that he will not seek a contract extension. Morse’s contract wasn’t extended last year, either. His annual salary is $131,500, in a district with 10 elementary schools, three middle schools and three high schools.

Morse’s efforts have been praised by some and criticized by others. Under his leadership, the district adopted a multi-year budget process, reorganized central office administration, and is expected to adopt a comprehensive plan in November that will establish clear benchmarks for success in the classroom and elsewhere.

“Jim has been a change agent,” said Kate Snyder, board chairwoman. “The dysfunction went deeper than any of us realized. The changes he’s made haven’t been easy, but they’ve been critical. Is it happening fast enough for everyone? Of course not. It never does.”

Snyder said the board will discuss Morse’s pending departure in another private meeting on Oct. 25, and hopefully have a plan by the end of December to find his replacement.

Whoever it is can expect to have it a lot easier than Morse, who typically works 16-hour days and has clashed with members of the school board and the public over budget preparation, curriculum selection, booster clubs and staff members’ accountability.

“The board has been very, very tough on him,” said Jaimey Caron, the board’s finance chairman. “The board wants to get to a better place quickly. I think we’re both disappointed that we couldn’t take better advantage of his talents, which are tremendous.”

Caron said progress was slowed by the bad economy and the magnitude of challenges on Morse’s plate, including a critical review of special education programs and a tradition of school principals operating autonomously.

“This is a terrible time to be overhauling a school system,” Caron said. “I don’t think people realize how much work is necessary to modernize the school system and position it to make the most of its potential. That being said, Jim has done a great job for us. He will leave a legacy that ensures the next superintendent has it much easier.”

Caron pointed to the success Morse had in negotiating new contracts with the district’s unions, including a teachers’ agreement that saved taxpayers nearly $2 million in salary concessions this year, allowed teachers to have more say in educational matters and gave students five more class days.

“He engaged the unions at a level that they respected what he was trying to do,” Caron said.

Bill Weber, a parent in Portland who pays attention to school issues, said he was surprised to learn that Morse is leaving so soon.

“To put systems in place and walk away, it’s hardly giving it a chance,” Weber said.

Weber questioned the effectiveness of Morse’s central office reorganization, saying that new titles assigned to many jobs were simply “an obvious attempt to move people out of positions without firing them.”

Weber also questioned the loss of advanced placement classes at the high school level and Morse’s decision to move Principal Mike Johnson from his long-time position at Portland High School to head Portland Arts and Technology High School.

“There were a lot of high hopes when (Morse) started, but I can’t say it’s paid off in the classroom,” Weber said. “I hope they hire a replacement who can stick around and see things through.”

Before coming to Portland, Morse was superintendent of RSU 18, which includes Oakland, China, Belgrade, Sidney and Rome. He was also superintendent of the Maine School of Science and Mathematics in Limestone.

A Portland native, Morse has homes in Portland and Unity.

He said he has no concrete plans for his retirement, but he’s cultivating job offers that he has continued to receive since taking the job in Portland.