Rabbi Pesach Pruskin was born in 1879 near Kobrin, after the death of his father, whose name he received. His mother was the granddaughter of Rabbi Moshe Tzvi Rabinowitz, rabbi of Antopol, with whom the family lived. As a youth he studied at the Radin yeshiva and then in Slabodka under Rabbi Nosson Tzvi Finkel, the Alter of Slabodka, and for a time at the Kelm Talmud Torah.

In 1897 the Alter sent fourteen of his finest students to form the nucleus of the new Slutsk yeshiva; Rabbi Pesach was among them. After his marriage he became a night watchman in an orchard, devoting his nights to study, until Rabbi Isser Zalman Meltzer called him back to Slutsk as mashgiach. There he was the primary teacher of the future Rav Moshe Feinstein, and was soon recognised as one of the most brilliant minds of his time.

On the Alter's advice he founded a yeshiva in Shklov, with a group of students chosen by Rav Meltzer. In 1911 the community of Amstislav invited him as rabbi; he accepted on condition that he could bring his yeshiva. When the region came under Soviet rule he returned to Kobrin, became its rabbi, and in 1923 founded the Kobrin yeshiva, which trained many students who became great scholars.

He passed away on 11 Cheshvan 5700 (October 1939), at the start of the Second World War.