In 1923, following the death of her first husband Stefan Szczucki in Lwiw, she settled in the village of Górki Wielkie in Cieszyn Silesia where in 1925 she married Zygmunt Szatkowski.

Kossak-Szczucka's historical novels include Beatum scelus (1924), Złota wolność (Golden Liberty, 1928), Legnickie pole (The Field of Legnica, 1930), Trembowla (1939), Suknia Dejaniry (The Gift of Nessus, 1939).

Best known are Krzyżowcy (Angels in The Dust, 1935), Król trędowaty (The Leper King, 1936), and Bez oręża (Blessed are The Meek, 1937) dealing with the Crusades and later Francis of Assisi, translated into several languages.

[3] In the summer of 1942, when the liquidation of the Warsaw Ghetto began, Kossak-Szczucka published a leaflet entitled "Protest," of which 5,000 copies were printed.

"All will perish ... Poor and rich, old, women, men, youngsters, infants, Catholics dying with the name of Jesus and Mary together with Jews.

[4] Regarding Kossak-Szczucka's "Protest", Robert D. Cherry and Annamaria Orla-Bukowska wrote in the introduction to Rethinking Poles and Jews: "Without at all whitewashing her antisemitism in the document, she vehemently called for active intercession on behalf of the Jews - precisely in the name of Polish Roman Catholicism and Polish patriotism.

The deportations from the Warsaw Ghetto precipitated her cofounding of Żegota that same year - part of the Polish Underground State whose sole purpose was to save Jews.

Kossak-Szczucka also wrote books for children and teenagers, including Bursztyn (1936) and Gród nad jeziorem (Settlement by the Lake, 1938).

In 2009, the National Bank of Poland issued a coin posthumously commemorating the work of Kossak, Irena Sendler and Matylda Getter in helping Jews (see Żegota).

Zofia's daughter, Anna Szatkowska (15 March 1928, Górki Wielkie – 27 February 2015), wrote a book about her experience during the Warsaw Uprising.