The Ploughshares Fund was founded in Sally Lilienthal's living room in 1981. Under her leadership, it set out to prevent the use and spread of nuclear, chemical and biological weapons. In the Fund's first year, Lilienthal raised $100,000 to distribute to individuals and small organizations to study and educate others about arms proliferation issues. Ploughshares was a major supporter of the International Campaign to Ban Land Mines, which led to the treaty that was signed by 122 countries and won the campaign a Nobel Peace Prize in 1997. By 2006, Ploughshares had distributed more than forty million dollars and had been instrumental in questioning the effectiveness of Patriot missiles during the Persian Gulf War, fighting the use of landmines, and in facilitating agreements on how to verify nuclear test bans.

Born in Portland, Oregon, Sally Lowengart grew up in San Francisco. She graduated from Sarah Lawrence College in 1940. During World War II, she worked in Washington D.C. in the Office of War Information writing radio dramas. Returning to San Francisco after the war, she married Arthur Cohen Jr., studied sculpture, and became a working artist.

Her first husband died in 1953. A second marriage ended in divorce. In 1970, she married Philip Lilienthal and worked with him to found the northern California chapter of the NAACP Legal Defense and Education Fund. Lilienthal also co-founded the San Francisco Museum of Modern Art's Rental Gallery and was serving as national vice-chairwoman of Amnesty International when that organization won the Nobel Peace Prize in 1972.

She had five children, two stepchildren, and eleven grandchildren.