Rabbi Yosef Shalom Elyashiv was born on 1 Nisan 5670 (1910) in Šiauliai, Lithuania, the only child of his parents after seventeen years of marriage. His father, Rabbi Avraham Levinson, became rabbi of Gomel; his maternal grandfather was the famous kabbalist Rabbi Shlomo Elyashiv, author of Leshem Shevo veAchlamah, whose scribe he became as a child when the old man's sight failed. In 1924 he moved with his family to Jerusalem, settling in Meah Shearim; to obtain a single family immigration certificate, the family took the name Elyashiv, his mother's maiden name. He married the daughter of Rabbi Aryeh Levine, the "Tzaddik of Jerusalem".

For many years he served as a judge on Israel's Supreme Rabbinical Court. His diligence was legendary: he studied some sixteen hours a day for decades, and gave classes in Talmud and Shulchan Aruch in a Meah Shearim synagogue. After the death of Rav Shach he became the leader of the Lithuanian yeshiva world and the "Posek HaDor", the halachic authority of the generation, consulted by the Orthodox world on every major question.

His responsa and Talmud notes have been published. He passed away on 28 Tammuz 5772 (2012), at a hundred and two; hundreds of thousands attended his funeral in Jerusalem.