Rabbi Yisrael Hager was born in Vizhnitz on 2 Elul 5620 (August 20, 1860). The son of Rabbi Baruch of Vizhnitz, he descended from the Ahavat Shalom of Kossov, Rabbi Naftali of Ropshitz and the Maggid of Mezritch, and was named after Rabbi Yisrael of Ruzhin. He studied under his grandfather, Rabbi Menachem Mendel, the Tzemach Tzaddik. In 5635 he married Hinda, daughter of Rabbi Meir Horowitz of Dzikov, author of Imrei Noam, and studied for a time in his father-in-law's home.

When his grandfather passed away in 5645, he became rabbi of Bedevla in Maramures. On the passing of his father in 5653 (1893), at the age of 32, he assumed the leadership of the Vizhnitz chassidim. Thousands of Jews from Bukovina, Galicia and Hungary belonged to his court, which drew crowds of visitors every year. He founded the Beit Yisrael yeshiva in Vizhnitz, headed by his son Rabbi Menachem Mendel.

During the First World War, sought by the Russian army, he fled to Kossov and then made his way to Grosswardein (Oradea) in Transylvania, where he remained for the rest of his life. He shared in the pain of the community and of each individual, rejoiced with every person, and multitudes came from all the neighboring provinces to stand in his shadow. His fervent prayers, especially on the festivals and the Days of Awe, and his melodies, still sung today, left their mark on the chassidic world. Known for his love of every Jew, he avoided disputes; he was among the leaders of Agudat Yisrael in its early days and gave approbations to dozens of books.

Works: Ahavat Yisrael, on the Torah and the festivals, published in Grosswardein in 5703, from which he takes his title; Or Yisrael, a collection of discourses.

He passed away on Friday night, 2 Sivan 5696 (May 22, 1936), and was buried in Grosswardein. On 13 Adar 5710 (1950) his remains were brought to Israel and reinterred in the Shomrei Shabbat cemetery in Zichron Meir, Bnei Brak, where an ohel was built over his grave. His sons, Rabbi Menachem Mendel, Rabbi Chaim Meir, Rabbi Eliezer and Rabbi Baruch, carried on his work.