Rav Yaakov Yitzchok was the son of Rav Yisrael Elimelech of Zhavna, and a scion of the Dombrover dynasty, who succeeded his father as Rebbe in the city of his rabbinical post of Zhavna.He became the son-in-law of Rav Meir Horowitz of Dzhikov, a descendant of the Ropshitzer dynasty.He was very popular, and thousands attended his levaya from nearby Tarnow.His sons were: Rav Sholom Dovid of Zhavna, Rav Yehuda of Sokolov, Rav Chaim Eliezer of Radlov and Rav Yisrael Yosef. His son-in-law was Rav Naftoli Horowitz of Pokshavnitza.

Rav Yaakov Yitzchok Unger