Five months after he was installed as principal of Harbor Middle School, Dr. Robert Martin was removed by the city’s school department, parents learned in a letter from Superintendent Carol Johnson.

Johnson’s letter, which parents received last week on the day before Thanksgiving, said the change in leadership was effective that day, Nov. 24.

“We know how critical leadership is to our overall student improvement efforts, and we acknowledge that this decision has implications for you, your children, and the dedicated faculty and staff of the Harbor,” she wrote. “We expect to appoint a permanent principal to the Harbor by no later than mid-January.”

The letter came the same day as a Reporter article noting that Martin had been put on administrative leave for two-and-a-half weeks. Boston Public School officials had declined to say if the leave was related to a defensive e-mail exchange with the parent of a special education student at the middle school, in which he chided the parent as “out of line” for saying the school does not have a plan for a “one-to-one” replacement for her son. His email, which was sent the day before he was put on leave, ran over 1,000 words.

Martin had worked at four local middle schools before taking over the Harbor Middle School over the summer. He received praise for his work at the O’Donnell Elementary School for improving standardized test scores, and Harbor Middle School officials said he was quickly turning around Harbor Middle School as well.

Designated as a “turnaround school” earlier this year in order to close student achievement gaps, the Harbor was established in 1998 as a pilot school in the Harbor Point Community Center. According to BPS documents, the school had “fairly acceptable” MCAS scores for the first six years, but struggled with facility issues, high faculty turnover, and administrative changes that caused a “dramatic decline” in the scores starting in 2005.

“It is our intent to make the Harbor a full inclusion middle school that serves as a place of learning and academic excellence for all students,” Johnson wrote in her letter. “The future principal of the Harbor will build on the strong foundation in place and sustain partnerships that have been established to achieve this goal. In the days to come we will create opportunities for families to inform the profile of the Harbor’s next leader.”

During the interim period, Boston Public Schools’ assistant academic superintendent Albert Taylor will become acting principal. He has led the Murphy K-8 School and the Mozart Elementary School. “He will work with staff and families at the Harbor to make this transition period as seamless as possible so that the education of your children remains our primary focus and priority,” Johnson wrote.