Israel Schorr was born to a Hassidic family in Khyrov, Galicia (now southern Poland, but then part of the Austro-Hungarian Empire, or Austro-Galicia). He began his cantorial life as a boy soprano, singing at the Hassidic courts of the rebbe (rabbinical-type leader of a Hassidic group or dynasty) of Chortkov (now Ukraine) and the rebbe of Rymanów. Later, in Lemberg (L’vov) in 1904, Schorr became the official cantor for the Rymanover rebbe, succeeding his distant relative, the esteemed and learned Hazzan Boruch Schorr (1823–1904).
During the First World War, Israel Schorr was in the Imperial army, and then he served cantorial pulpits in Brunn (now Brno, in the Czech Republic); Kraków; Piestany, west Slovakia; and Zürich. In 1924 he emigrated to the United States, where he was the cantor at important synagogues in Chicago and New York. During his American years, Schorr created a number of his own pieces, exploiting florid cantorial idioms and quasi-improvisatory vocal lines. Some of those pieces were extended and expanded by other virtuoso cantors, and in their subsequent forms they became well known in concert versions and through recordings. Accompaniments and interludes were sometimes added by these performers or by other arrangers, and these also came to be associated with the pieces.