Career
He is one of the most highly respected Orthodox rabbis in the world and one of the most important leaders of the Haredi world. His beis din (rabbinical court) handles all kinds of matters, such as financial disputes, marriage conflicts, and conversions. Rabbi Karelitz is a nephew of Rabbi Avrohom Yeshaya Karelitz, known as the Chazon Ish.
(The latter"s sister was Rabbi Nissim"s mother).
The Chazon Ish was a previous rabbinical spiritual leader of Bnei Brak. From the time of the Chazon Ish until Rabbi Nissim Karelitz it was Rav Elazar Shach who was regarded as the pre-eminent leader.
In his youth, he studied in the Ponevezh Yeshiva.
