Rabbi Yitzchak Isaac HaLevi Rabinowitz was born on 11 Tishrei 5608 (21 September 1847) in Ivyanets, near Minsk, in present-day Belarus. His mother, Rachel, was the daughter of Rabbi Mordechai Eliezer of Kovno, author of Karnei Re'em. His father, Eliyahu HaLevi Rabinowitz, was killed when the boy was very young, and he was raised by his grandfather.

He began studying Gemara at the age of five and a half. At thirteen he entered the Volozhin yeshiva, where he studied for a year under Rabbi Yosef Dov Soloveitchik, the Beis HaLevi. Married at eighteen, he earned his living in the tea trade while continuing to learn. Around the age of twenty he became gabbai of the Volozhin yeshiva, and he later helped bring about the appointment of Rabbi Chaim Soloveitchik as its head.

In 5655 (1895) he left Russia for Pressburg (Bratislava), where he began writing his major work, Dorot HaRishonim. In 1902 he settled in Hamburg. He corresponded regularly with the leading rabbis of his time, including Rabbi Chaim of Brisk, Rav Kook and Rabbi Chaim Ozer Grodzinski. From 1906 he urged rabbis throughout Europe to unite the Orthodox communities in a worldwide organization; this effort led to the founding of Agudath Israel, and he took part in the Kattowitz conference of 1912, earning the title of father of Agudath Israel.

Dorot HaRishonim is a history of the transmission of the Jewish tradition, written to defend the traditional view against historians of the Wissenschaft des Judentums such as Zacharias Frankel, Heinrich Graetz and Isaac Hirsch Weiss. The volumes appeared out of chronological order beginning in 1897, and some were published after his death. He also wrote Batim Levadim, on the rules of doubt in halachah.

He passed away in Hamburg on Friday night, 20 Iyar 5674 (15 May 1914), following a heart attack. At his request, no eulogies were delivered.