Rabbi Yaakov Yisrael Kanievsky was born in the Ukrainian town of Hornosteipel, from which his appellation, "the Steipler", was later derived. He was the son of Reb Chaim Peretz, who was the local shochet, and a Chassid of the Tzaddikim of the dynasty of Chernobyl, particularly the Rebbe of Hornosteipel, Rabbi Mordechai Dov Twersky. At the age of 11, Rabbi Yaakov Yisrael entered the Novardok yeshiva, studying under its famed Rosh Yeshiva, Rabbi Yosef Yozel Horowitz, known as the Alter of Novardok.

In 1917, when Rabbi Yaakov Yisrael was barely 18, he was already renowned for his scholarship and piety. His Rosh Yeshiva sent him to establish a branch of the Novardok Yeshiva in the city of Rogochov. However, the Bolshevik Revolution was in full swing and Rabbi Yaakov Yisrael was conscripted into the Red Army. Rabbi Yaakov Yisrael lived under extremely harsh conditions and was frequently beaten for his strict religious practices and high standards, but nevertheless did not deviate one iota from his agenda of serving G-d, regardless of the difficulties.

After his discharge Rabbi Yaakov Yisrael moved to Bialystok in Poland in order to continue learning Torah unhindered from Communist interference. There, he studied under Rabbi Avrohom Jofen, the son in law of Rabbi Yosef Yozel Horowitz. In 1925, Rabbi Yaakov Yisrael Kanievsky published his first sefer Shaarei Tevunah which was received with great acclaim in Yeshiva circles. The Sefer eventually reached the great Rabbi Avraham Yeshayahu Karelitz, the Chazon Ish, who lived in Vilna. Without even meeting him, Karelitz decided that the author was worthy of marrying his sister Miriam and invited him to Vilna to meet her. They married soon after. After his marriage Rabbi Yaakov Yisrael Kanievsky was appointed the Rosh Yeshiva of the Novarodok Yeshiva in the city of Pinsk which had become part of Poland in 1920 after the Polish-Soviet War.

In 1934, his brother in law, the Chazon Ish, who had already been living in Palestine for a while, urged Rabbi Yaakov Yisrael to join him. Rabbi Yaakov Yisrael Kanievsky moved with his family to be near the Chazon Ish in the newly established city of Bnei Brak. The Steipler shunned publicity and lived in humble surroundings. He devoted the rest of his life to teaching, writing his Torah thoughts, and attending to the multitude of petitioners who came to his home seeking advice and blessings.

When the Steipler passed away in 1985 he was acknowledged as one of the generation's greatest men. Over 150,000 mourners attended his funereal.

Rabbi Yaakov Yisrael Kanievsky had tremendous concern for the poor families of Israel, and the Rabbi Meir Baal Haneis Salant charity fund. Rabbi Kanievsky is a signatory on the historic 1979 Kol Koreh (broadside) on behalf of Rabbi Meir Baal Haneis Salant, together with such Torah giants such as Rabbi Moshe Feinstein, Rabbi Yaakov Kamenetsky, Rabbi Shloma Zalman Auerbach, Rabbi Elazar Simcha Wasserman, Rabbi Dovid Povarsky, Rabbi Yechiel Michel Feinstein, Rabbi Moshe Shmuel Shapiro, Rabbi Shmuel Birnbaum, and many, many others. May their memory be a blessing to all.