Her Shakespearean roles included Ophelia in Hamlet and the Queen in Richard II. Her film credits include Butterfield 8 (1960), A Rage to Live (1965), Rabbit, Run (1970), Sounder (1972), Top of the Hill (1980) and Daniel (1983). She appeared on television in six episodes of Alfred Hitchcock Presents (1955-65). She also appeared in the 1963 TV series The Fugitive and a 1961 episode of The Twilight Zone. One of her more famous roles was as Colonel Lilian Rayborn on Episode 150 of M*A*S*H. Her last role was in the Last Best Year (1990) with Mary Tyler Moore and Bernadette Peters.
In 1975, Mathews set up and ran a residential summer camp for disadvantaged children on her 100-acre farm in Redding, Connecticut. Toward the end her of life, Mathews, a passionate Environmentalist, made a perpetual donation of her 100-acre New Pond Farm to the Redding Land Trust, to ensure that it would retain its woods, fields, pond and marsh. The United Nations Association of the United States of America named Mathews one of Connecticut's outstanding women in 1987.
Mathews died at her farm in Redding, Connecticut in 1995, aged 84, from undisclosed causes.
