She resigned effective Jan. 17, said Ivan M. Lui-Kwan, chairman of the school's board of trustees.

Lui-Kwan said Matsunaga told the board she felt she had completed the tasks she set forth when she was hired, and wanted to move on to other challenges.

He said Matsunaga was hired to write a business profile as well as enhance the financial operations of the school and had done both.

Lui-Kwan has appointed two board members to head a search for a new leader, but in the meantime he is spending about five hours a day at the school to make sure there's a smooth transition. Lui-Kwan expects an interim Head of School to be appointed by the end of this school year.

A letter is being drafted that will go to parents in the next few days, but teachers and staff have been informed, he said.

Matsunaga was originally hired in July 2004.