In 1914, Katz went to the Volozhin Yeshiva for two years where he was ordained by Rabbi Refael Shapiro, the son-in-law of the Netziv.

In 1920, Katz assisted his father in law in the founding of a preparatory school for young men (Mechina), which would prepare younger students for study in the yeshiva proper.

In 1934, Katz was one of the founders of the Zeirei Agudath Israel in Lithuania and he served as the head of the Board of Action (Va'ad Hapoel).

Together with his brother in law, Rabbi Eliyahu Meir Bloch, he also served as one of the editors of the Agudah newspaper in Lithuania: "Dos Yiddishe Lebben".

In 1940, Katz and Eliyahu Meir Bloch managed to travel out of Soviet occupied Lithuania and make their way to the United States, in the hope of re-establishing the Rabbinical College of Telshe and bringing over its faculty and student body.

Towards the end of the war Katz discovered that his wife and 10 children had been killed by Nazi forces in Telz in 1941.