A two-time state principal of the year who adopted an in-depth teaching model known as Expeditionary Learning at King Middle School is retiring, Portland School District officials announced Tuesday.

Michael McCarthy, who became principal at King in 1988, was Maine’s Principal of the Year in 1996 and Middle Level Principal of the Year in 2010. In 2010, he was a finalist for National Principal of the Year.

“Mike came in with a vision for King Middle School and the work he did there with staff really transformed not only King but also has made a lasting impact on public education, not just in our district but nationally,” said Portland Public Schools Superintendent Emmanuel Caulk. “Mike is an outstanding educational leader who will be missed.”

Students at King tackle subjects in eight- to 12-week Expeditionary Learning programs that require them do research, work within the community and present their work to audiences.

“King Middle School is a great place and I have been honored to serve there for 27 years,” McCarthy said. “I am very proud of what we have accomplished at King.”

Before joining the Portland Public Schools, McCarthy was principal of Bonny Eagle Middle School in West Buxton from 1980 to 1988 and assistant principal at Waterville High School from 1977 to 1980. From 1973 to 1977, he taught at Roberts Junior High School in Medford, Massachusetts.