Ruth was born in the Ohel Moshe neighborhood in Jerusalem on June 9, 1929 to a Sephardic family with deep roots in the city. Her father, Eliahu Yifrach, had a store in the commercial center, but Arab rioters burned it down after the UN voted in favor of the Partition Plan. Her mother Rachel died when Ruth and her brother were still young. Her grandfather was Rav Benzion Cuenca, the rabbi of the city of Hebron and head of the rabbinical court in Jerusalem. She studied in the Alliance School and in an English school.
In 1946, she joined Lehi, after her brother Nissim Yifrach (a fellow member of Lehi known by the nom de guerre Shaul) was arrested and sent to Latrun. (He died in 1971.)
She was in Department 6, headed by David Seton (Geshuri). When Lehi camps were established in Jerusalem, in Lifta and in Sheikh Badr, she was a combat medic in Dr. Hefner and Nurse Rina’s clinic. She took part in the battle for the Old City, on 15 May 1948. After Lehi was disbanded, she enlisted in the IDF and served in Israeli Air Force.
When she was demobilized, she went to work in the Jewish Agency in Jerusalem, retiring, in 1987, after thirty years.
In 1953, she married Yaakov Yahalom, a former member of Lehi whose nom de guerre was Gilad, whom she knew from their days in the underground. They lived in Jerusalem, the city of her birth.
Ruth and Yaacov had three daughters and many grandchildren