Rabbi Tzvi Hirsh Rabinowitz, affectionately called Rabbi Hirshel, was born in 5608 (1848) in Nesvizh, where his father, Rabbi Yitzchak Elchanan Spektor, was then serving as rabbi. A child of exceptional intellect and memory, he was taught Torah by his father himself. At eighteen he married Chiena, daughter of Rabbi Meir Saltz of Salchnik near Vilna.

Unwilling to make the Torah a source of livelihood, he first went into business in Kovno while serving as his father's right hand in all the affairs of the rabbinate. From 5637 to 5640 (1877-1880) he directed the Kovno Kollel founded under his father's auspices. When his business collapsed in 1880, he accepted the rabbinate of Mitau in Courland. In 5647 (1887) he was put forward, with the backing of several leading Lithuanian rabbis, for the post of chief rabbi of the Eastern European congregations of New York, but Rabbi Yaakov Joseph was ultimately chosen. In 5649 (1889) he became moreh tzedek and maggid of Vilna.

When his father died in Adar 5656 (1896), he succeeded him as rabbi of Kovno. An opponent of the Musar movement, he founded the Knesses Beis Yitzchak yeshiva in the city, named after his father. Halachic questions reached him from all over Russia and Germany, and he granted semichah to the members of the Kovno kollel. He also intervened with the Russian authorities against decrees threatening the chadarim and against the expulsion of Lithuanian Jews from Courland.

A pleasant man of fine character, he loved truth and peace and never flattered anyone; he was content with little and refused all gifts. Nearly all his many Torah writings were lost during World War I, and only a few responsa survive, chiefly in his father's Ein Yitzchak.

He passed away in Kovno on 2 Shevat 5670 (January 12, 1910) and was buried there beside his father.