The Board of Trustees of Marymount has the ultimate responsibility for the establishment of school policy, which is then implemented by the administration. In addition, the Board oversees the financial operations of the school and raises funds necessary for the school's operation and future development. The Board is made up of members chosen from past and present parents, alumni, and persons whose expertise will be of value to the school. The Headmaster and the Presidents of the Marymount Parents' Club serve as ex-officio members of the Board.

President: Tisha Ford
First Vice President: Joe Fazio
Second Vice President: J. Roger Battistone
Treasurer: Tom Pickett
Secretary: Meg Bradley