Born Ada Fishman in Mărculești in Bessarabia Governorate, Russian Empire (in present-day Moldova), Maimon made aliyah to Ottoman-controlled Palestine in 1912, and was followed by her older brother, Yehuda the following year.

A participant in its founding convention, she also served on the executive committee of the Histadrut trade union.

Between 1946 and 1947 she served as head of the Histadrut's aliyah department, travelling to Displaced persons camps in Germany and Cyprus.

In addition, she was a member of the Women's International Zionist Organization's leadership.

Having served as a member of the Assembly of Representatives during the Mandate era, Maimon was elected to the first Knesset on the Mapai list in 1949.