Eleanor Lansing Dulles was born in Watertown, New York, one of five children of a Presbyterian minister and his wife. Among her brothers was John Foster Dulles, the future U.S. Secretary of State. She graduated from Bryn Mawr College and then went to France in 1917 to help with World War I relief efforts. She returned to Bryn Mawr to earn a master's degree in labor and industrial economics. She held various jobs in the early 1920s, such as punch press operator at the American Tube & Stamping Company in Bridgeport, Connecticut and payroll clerk for a hairnet company in Queens, New York. She also traveled extensively in Europe and studied at the London School of Economics. Back in the USA, she earned a master's degree from Radcliffe College and a doctoral degree in economics from Harvard with a thesis on the French franc later published as The French Franc, 1914-1928 (1928). For ten years, she taught economics and finance at the Wharton School of Business at the University of Pennsylvania, Simmons, Bryn Mawr, and in Europe. She wrote scholarly books, including Depression and Reconstruction (1933). At age 30 she met David Simon Blondheim, a linguistics professor at Johns Hopkins University and Orthodox Jew, whom she married in 1932 against the wishes of both families. She continued to use her maiden name and was known as Mrs. Dulles. Not long before the birth of their son in 1934, her husband committed suicide. She entered government service in 1936 as director of financial research for the Social Security Board. She moved on to work for the State Department, where she remained for the next 20 years. She was a prominent member of the USA delegation at the 1944 Bretton Woods international monetary conference.
She is best known for the major part she played in planning and carrying out the post-World War II reconstruction of West Berlin in the 1950s. She obtained funding for cultural and economic programs and helped to reduce West German unemployment and increase production. The new Berlin Congress Hall she sponsored was nicknamed by Berliners the ''Dulleseum'' and ''Frau Dulles's Hut.'' In 1959, she was assigned to study U.S. foreign aid programs and visited 60 countries on behalf of the Bureau of Intelligence and Research.
She left the State Department in 1962, after her brother Allen had been dismissed from the C.I.A. in the wake of the Bay of Pigs disaster. She wrote several books on U.S. foreign policy and in 1963 published a study of her brother's final year at the State Department, John Foster Dulles: The Last Year. She wrote a memoir called Eleanor Lansing Dulles: Chances of a Lifetime (1980).