The trustees of the University of the District of Columbia selected the board's executive director last night as interim president, marking the fourth time in the school's 13 years that a temporary chief executive has been appointed.

In closed session, the board chose Miles Mark Fisher IV to serve as UDC's chief executive officer until a permanent president is selected to replace Rafael Cortada. The board fired Cortada in May, citing "management blunders" and "fiscal mismanagement."

The board selected Fisher, 57, over two members of the Faculty Senate, including an executive who was hired during the controversial firing of Cortada, and Claude A. Ford, UDC's vice president for institutional advancement, who has twice before served as interim president.

Fisher has worked for the board of trustees since 1985, the last year as executive director. His selection is likely to draw criticism from some in the university community because of his close ties to the board.

Nira Hardon Long, the board's chairman, said Fisher had overwhelming support among the trustees. "We feel that we selected the best qualified person," Long said. "I don't feel it makes a difference where he has been."

A presidential search committee has not yet been formed, but Long said she hoped to have the job filled by fall 1991.