Emily Greene Balch was born on January 8, 1867, in Jamaica Plains, Massachusetts. She was one of six children born to parents, Francis V. Balch and Ellen Noyes Balch. She had four sisters and one brother. Her father was a successful lawyer, and a secretary to abolitionist U.S. Senator Charles Sumner (R-MA) during the Civil War. Unfortunately, when Balch was seventeen years old, her mother died while giving birth to a child who also died.

As a child, Balch grew up in a Unitarian household, which influenced her to use her intellect for good works. She had tutors, went to Miss Catherine Ireland's Private School in Boston, and was able to read adult books by the time she was nine years old. She also attended a private bible class where she learned from Minister Charles Fletcher Dole, whose main message was to serve goodness no matter the cost. Judith Stiehm quotes Balch describing Dole as "the chief of all the influences that played upon [her] life," and as "a preacher of good-will in the sense of unceasing active willing of good," (Stiehm Champions for Peace).

Balch continued her schooling at Bryn Mawr College. Her initial interests were in literature and sketching; however, she eventually decided to study economics. When contemplating what she had learned and what she wanted for her next year, Balch said, "I long for reverence, humility, purity, truthfulness, simplicity, strength, wisdom, love, providence, gladness, regularity," and "I hope I shall not get lost in study or pursue it for pleasure beyond its best measure for my purpose, unknown to me as yet." Three years after her entrance, Balch became a member of the college's first graduating class in 1890 and was awarded Bryn Mawr's initial Fellowship for one year's study in Europe. Although she did not think she deserved it, Balch took the Fellowship and went to Paris, France, where she worked with Emile Levasseur to study Paris's economy. She then used her research to write a book entitled Public Assistance of the Poor in France (1893).

When Balch returned, she did social work with the Boston Children's Aid Society. During this time she also co-founded the Dennison House Settlement and served as its first headworker. She then spent a summer in school studying applied ethics where she met Jane Addams and decided to complete her formal studies. She did this through classes at Harvard University and the University of Chicago. She then spent a full year, funded by her father, working in economics in Berlin.

In 1897, Balch became a professor at Wellesley Women's College where she worked until 1918. She was an excellent teacher; she created her own courses that taught sociology and economics through fieldwork and volunteering. According to one of her students quoted by David and Selvidge,

Miss Balch was an utterly unpretentious woman, spare of figure, unmindful of clothes and fripperies. Besides her learning, which was broad and deep, she had a very wide personal acquaintance with civic and humanitarian leaders in Europe as well as America...Professor Balch would frequently overlook some of the mechanical details of teaching...[but] her teaching was all the more better for her excursions into the buzzing centers beyond the placid college walls.

During her time as a professor she also helped found the Women's Trade Union and served on municipal boards and state commissions. She contributed to movements for women's suffrage, racial justice, and child labor.

Balch took a two-year leave from Wellesley to study the Slavs and write about her research (Our Slavic Citizens, 1910). Then, as World War I broke out, Balch became even more concerned with peace than ever before; she became involved in the American Union Against Militarism, the Women's Peace Party, and the International Congress of Women at The Hague. During this time Balch worked with Jane Addams and Alice Hamilton to write Women at The Hague: The International Congress of Women (1916).

Balch asked for an extension of her leave, but Wellesley decided to terminate her contract instead. She accepted an editorial position for the magazine The Nation, and wrote another book called Approaches to the Great Settlement (1918), about the problems with peace after World War I and the stabilization of Europe. She also attended a second convention for the International Congress of Women, at which they decided to organize themselves as the Women's International League for Peace and Freedom (WILPF), for which Balch agreed to become the international secretary-treasurer.

Between the wars, Balch continued her work with international organizations and commissions of various types; she edited, and wrote most of, Occupied Haiti; and she tried to find ways to help victims of Nazi persecution. In 1946, Balch won the Nobel Peace Prize for all of her work for peace with the WILPF. She shared the prize with John R. Mott who received the prize for his work in establishing and strengthening international Protestant Christian student organizations that worked to promote peace. She took her $17,000 share of the prize money and gave it to the WILPF.

After receiving the prize, Balch continued her activism despite her frail health. She worked with the WILPF as the honorary chairwoman. In 1959, she served on a commission that organized the 100th anniversary celebration in honor of Jane Addams's birth. Balch entered Mr. Vernon Nursing Home in Cambridge, Massachusetts, in 1961, where she died of pneumonia at age 94.