Spellman was active in the fight for a home rule charter form of government for Prince George's. In 1962, running on a reform slate, she served as a member of the Prince George's County Board of Commissioners from 1962 to 1970. She served two years as chairman, effectively the head of the county's government. After the establishment of the County Council, Spellman served as councilwoman at large from 1971 to 1974. She was appointed by President Lyndon B. Johnson to the Advisory Commission on Intergovernmental Relations in 1967 and was awarded the highest honor that could be bestowed by county officials nationwide when she became the first woman elected president of the National Association of Counties in 1972.
