Sonia Swanson was born in Providence, Rhode Island in 1924. She attended Brown University where she received a B.A. in English in 1945. She later attended the University of Buffalo where she received a master's degree in Vocational Rehabilitation Counseling. Swanson worked for several years as a teacher. In 1967 she joined the New York State Employment Service and later transferred to its Office of Vocational Rehabilitation. Swanson was also deeply committed to the National Organization for Women (N.O.W.); she was a long-standing active member and officer of the group.

A member of the Buffalo Chapter of N.O.W., she became President in 1972. In late 1973 an offshoot of the Buffalo Chapter formed, called the Erie County Suburban Chapter. Swanson appears to have been instrumental in the founding of this group; she became the first treasurer as well as editor of Notes, the Chapter newsletter. Swanson also served as convener of the New York State Committee on Marriage and Divorce (1974). She also held the position of New York State N.O.W. secretary for 1977/1978. The papers end abruptly a few months prior to her untimely death on October 7, 1978.