Mildred Scott Olmsted, peace activist and suffragist, was born in Glenolden, Pennsylvania, on December 5, 1890. She attended Friends' Central School in Philadelphia and graduated from Smith College in 1912 with a degree in history. In 1913, she received a certificate from the Pennsylvania School of Social and Health Work. In 1919, she went to France with the YMCA where she organized recreation for soldiers at the Sorbonne. It was while in Paris that Olmsted first met Jane Addams. In 1920, she went to Berlin and joined the German Unit of the American Friends Service Committee, American Relief Administration. Here, she helped organize the feeding of famine-stricken Bavarian children. Returning home, Olmsted became Assistant Director of the White-Williams Foundation from 1920 to 1922. She married Allen S. Olmsted, 2nd, in 1921 and the couple had one child and adopted two more.
In 1922, Olmsted became Executive Secretary of the Pennsylvania Branch of the Women's International League for Peace and Freedom (WILPF). She assumed additional responsibilities in 1934 when she became National Organization Secretary of WILPF, U.S. Section. In 1946, Olmsted became National Administrative Secretary when Dorothy Detzer resigned. She held that position (title changed to National Executive Director circa 1964) until her retirement in 1966. She remained active as Executive Director Emerita of WILPF and also served on its International Executive Committee from 1937 until 1953.
While she was best known for her leadership in WILPF, Mildred Scott Olmsted served many organizations. She was on the Board of Philadelphia SANE, Promoting Enduring Peace, the Upland Institute of Crozer Seminary in Chester, Pennsylvania, vice-chairman of the Pennsylvania American Civil Liberties Union, and representative to the United Nations Council of Non-Governmental Organizations, among others.
An early leader in the birth control movement, Olmsted helped set up the first clinic in the Philadelphia area. She championed the causes of women's suffrage, civil liberties, the protection of animals, and conservation of natural resources. Her hobbies included gardening, travel, antiques, and historic preservation.
In 1972, Olmsted was presented with the Philadelphia SANE Peace Award, and in 1974, her alma mater Smith College presented her with an honorary doctorate degree, as did Swarthmore College in 1987. She was honored on numerous occasions by WILPF and received its first Lifetime Achievement Award in 1986.
Olmsted resided for most of her life in Rose Valley, Pennsylvania, a suburb of Philadelphia. She was a member of the Society of Friends and attended the Providence (Media, Pennsylvania) Meeting where she served as clerk. She was a member of the Philadelphia Yearly Meeting Committee on Reorganization in 1973 and 1974 and also served on the Executive Committee of the Peace Education Committee of the American Friends Service Committee.
Olmsted died July 2, 1990, at the age of 99.