She studied first at Bennett Junior College and then in London at the Royal Academy of Dramatic Artist
She began her professional acting appearance with the Stratford-on-Avon Shakespearean Company before moving back to the United States. Her Shakespearean roles included Ophelia in Hamlet and the Queen in Richard World War II Her film credits include Butterfield 8 (1960), A Rage to Live (1965), Rabbit, Run (1970), Sounder (1972) and Daniel (1983). Matthews has also appeared on the Alfred Hitchcock series in "Conversation Over a Corpse", as well as the 1963 television series The Fugitive.
One of her more famous roles was that of Colonel
Lilian Rayborn on Episode 150 of M*A*South*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. Because of her philanthropic activities in education, the United Nations Association of the United States of America named her one of Connecticut"s outstanding women in 1987.