Mary C. Goodwillie was born in Cleveland, Ohio in 1870, the daughter of Mr. and Mrs. Thomas C. Goodwillie. She attended Miss Hershey's School in Boston, there developing a love and appreciation of literature. She came to Baltimore with her family in 1898.

Goodwillie was for many years active in the Family Welfare Association and from 1924-1945 was president of the Baltimore Social Service Exchange. She was also president of the Friends of the Johns Hopkins University Library, and during World War I she organized the Red Cross Home Service. For many years she was active in the Community Fund from which she was a distinguished service medal in 1938. Goodwillie was instrumental in establishing the Junior League of Baltimore, the Contemporary Club, and the Baltimore Poetry Society. She was very much interested in music and the theater.

For many years she was on the Board of the Women's Auxiliary of Johns Hopkins Hospital, and outstanding among her services to the Hospital was her reorganization of the Medical-Social Services Department. In 1940 she was given an honorary M.A. degree by Johns Hopkins University in recognition of her many contributions not only to Hopkins but to the community. For a time she gave courses in Social Economics at the University. She died on June 28, 1949 and left a legacy to Johns Hopkins of $10,000. To honor Goodwillie's memory, the Goodwillie Room was opened in Gilman Hall in October 1949 as a special library reading room and lounge. Formerly used as a meeting room for the Board of Trustees, the room was designated as the meeting place for the Friends of the Library.