She then studied at the Warsaw University, before the Nazi German and Soviet invasion of Poland.
Later, Baniecka was an activist with the Intervention Bureau of the Polish Workers" Defence Committee (Polish: Komitet Obrony Robotników, KOR) in 1977. Her parents were not religious, nevertheless, she went to a Catholic school. Zofia had many Jewish friends from assimilated homes just like her own intellectually inclined parents.
In late 1940 the Nazi occupiers ordered the family to relocate when their home fell within the boundaries of the newly established Warsaw Ghetto.
All three family members began to work for the Polish underground. Zofia"s inconspicuous grey-haired mother was transporting weapons in her shopping bag for the Resistance, while Zofia"s father smuggled food and books to friends in the Ghetto.
Thanks to help from their underground contacts, the family soon moved to a large apartment with four rooms and a kitchen — near the walls of the ghetto — and began taking in Jewish refugees. The apartment was divided by curtains with a different Jewish family behind each one.
Nobody was ever refused: friends, strangers, acquaintances.
Zofia got involved with the underground press and also, helped the Jewish Committee find hiding places for the children. As a courier, she distributed underground newspapers and relayed orders around the General Government. Even though in 1941 Zofia"s father was killed in a Soviet air-strike on Warsaw — from winter of 1941 till August 1944 (when the Warsaw Uprising started) — the two women managed to rescue at least fifty (50) Jews in their home, including a family of ten, escaping the Ghetto firestorm in April 1943 following the failed Ghetto Uprising.
When their house was full, the Banieckis helped Jews find other places to hide.
Ultimately, she also became an active participant in the Polish Solidarity movement of the 1980s.
In her professional capacity, Baniecka was a long-time member of the Warsaw chapter of the Association of Polish Artists and Designers (ZPAP). After the Soviet takeover of Poland at the end of World World War II, Zofia was arrested by the Communist authorities as a member of Resistance. But, was ultimately released.