Born in 1923 in Fort Worth, Stevenson attended the Madeira School in McLean, Va., and Sarah Lawrence College in Bronxville, N.Y. After graduation, she married J. Lee Johnson III of Fort Worth, although the marriage ended in divorce in 1980. Her second husband, John (Jack) Stevenson, died in 1997. At the death of her father, Stevenson became president of the Amon G. Carter Foundation. essentially founded the Amon Carter Museum of American Art in Fort Worth and chaired its board for decades. Survivors: Her children, Sheila Broderick Johnson, J. Lee Johnson IV, Catherine Lehane Johnson and Mark Lehane Johnson, all of Fort Worth, and Karen Johnson Hixon of San Antonio; 11 grandchildren; and five great-grandchildren..