PORTLAND — King Middle School Principal Mike McCarthy learned this week that he is one of three finalists for 2011 National Middle School Principal of the Year.

In April, the Maine Principals’ Association named McCarthy the 2010 Middle Level Principal of the Year in Maine.

The state award recognized McCarthy’s leadership in transforming a diverse, urban school from below-average to above-average performance on state reading, math and science tests using the Expeditionary Learning model.

The national award will be presented in October during a principals’ institute and awards banquet in Washington, D.C.

McCarthy, who lives in Hollis, was one of four finalists for the national award in 1997, after he was named Maine’s Principal of the Year in 1996, when the award recognized middle- and high-school administrators.

McCarthy’s reputation as an expert on school reform has only grown since then. He has lectured in 31 states, Canada and Bermuda, and he has hosted visitors from Ireland, England, Sweden, Australia and Japan who were interested in King Middle School’s success.

He’s also an adjunct professor in the educational leadership program at the University of Southern Maine and a national faculty member for Expeditionary Learning.