Rabbi Zalmanowitz was born in Tomaszow, Poland. In his youth, he studied with the author of Avnei Nezer and Eglai Tal, Rabbi Avraham from Sochaczaw, where he became known as an illui. At 17, he received semikhah from Rabbi Eliyahu Chaim Meisels zt”l, rabbi of Lodz. Besides his greatness in Torah, he was known for his piety and was among the distinguished chassidim of the Rebbe of Gur.

He came to the United States in 1921 and was appointed a rosh yeshiva at Rabbi Isaac Elchanan Theological Seminary in 1927. He taught hundreds of students during his 20 years there. He also served as rabbi at Kehillat Beit Aharon and Beit Haknesset Anshei Emet in Williamsburg, New York.

He was active in the Agudath HaRabbonim, as well as other organizations of Torah and chesed. He was instrumental in the successful efforts to save the Gerrer Rebbe zt”l and part of his family from the hands of the Nazis. Rabbi Zalmanowitz passed away on Erev Yom Kippur.