Elyashiv's rulings left a deep mark on many Jews who followed his interpretation of religious writings concerning contemporary issues; for example, whether to keep a patient on life support. Other decisions influenced Israeli politics, as the rabbi was the head authority of United Torah Judaism, a small but powerful political party.
"The people of Israel have lost a great rabbi, a sharp ruler and a man of outstanding wisdom," Prime Minister Benjamin Netanyahu said in a statement. "We grieve his passing."
Born in Lithuania in 1910 to a line of rabbinical scholars, Elyashiv settled in the ultraorthodox Jerusalem neighborhood of Mea Shearim after moving to Palestine with his family in 1924.
He was mostly a self-taught scholar. After holding a seat on the high rabbinical court for more than two decades, he immersed himself in study and what he would become most known for, rabbinical ruling on practical religious issues.
Respect for his rulings grew and gained uncommon consensus among the splintered orthodoxy, many heralding the luminary as a pillar of the Jewish people in contemporary times. Elyashiv was considered a literal interpreter of texts and a conservative arbiter. He objected to academic colleges for Torah scholars and opposed disconnecting brain-dead patients from life support, ruling that it constituted murder.
Despite rising to great importance, the renowned leader of the Lithuanian stream of ultraorthodoxy adhered to his modest lifestyle in the same two-room apartment where he had he raised his large family and received followers seeking blessings and answers to religious queries. As he grew frail, a small synagogue was erected near his home to allow him to continue his teachings.
Described as a humble man, Elyashiv did not court a public standing. Yet he became a key figure in Israeli politics with the formation of United Torah Judaism, an ultraorthodox political party that would often be a pivotal member of governments. As the party's supreme authority, Elyashiv held sway over government as its lawmakers acted on his instructions.
In 1999, he supported the party joining the left-leaning government of Ehud Barak. Later, he instructed the party to join Ariel Sharon's government despite his objection to its plan for disengagement from Gaza and the West Bank, in return for keeping secular studies out of ultraorthodox schools.
Elyashiv is survived by 10 children and numerous grandchildren and great-grandchildren.
Sobelman is a news assistant in The Times' Jerusalem bureau.