The Jews of Nieśwież were engaged in small trade, commerce, agriculture, and crafts. Due to World War I, the economic crisis in Poland, and the antisemitic policy of the Polish government the economic situation of the Jews declined. Consequently, many of them needed help from the American Jewish Joint Distribution Committee or from local Jewish aid organizations.
There was a wide range of Jewish political activity in the town. In addition to the Zionist Poalei Zion and Mizrahi parties and the Hehalutz movement, Nieśwież had branches of Agudat Yisrael and the Bund. All these sponsored educational and cultural activities. The town also had Yiddish and Hebrew schools, a Talmud Torah, and a Jewish library.
In September 1939, in the wake of the Molotov-Ribbentrop Pact, Nieśwież was annexed to the USSR. The Soviet authorities banned political activity and closed Jewish educational institutions. In place of the latter a unified Soviet Jewish school was established with instruction in Yiddish, which was soon replaced by Russian.
Nieśwież was occupied by the Germans on June 27, 1941. After a number of mass murders of local Jews the Germans forced the remaining Jews into a ghetto that was established, in early November of that year, by surrounding a synagogue with a fence. On July 22, 1942 the Germans, together with their Belarusian accomplices, began to liquidate the ghetto. When inmates of the ghetto refused to obey German orders, the Germans opened fire. This was met with armed resistance. Many of the ghetto’s Jews were wounded or killed in the revolt, but dozens of Germans and their Belarusian helpers were also killed. About 25 of the resisters escaped to the forest and joined Soviet partisan units.
Nieświeź was liberated by the Red Army in July 1944.