The distinguished Russian-born American conductor, Jascha Horenstein, began his musical training in Königsberg as a piano student of his mother, and he also studied with Max Brode. In 1911 his family moved to Vienna, where he studied philosophy at the University and, starting from 1916, was a pupil of A. Busch (violin), Joseph Marx (music theory), and Franz Schreker r (composition) at the Vienna Academy of Music. He then continued his training with Franz Schreker at the Berlin Hochschule für Musik (1920).
From 1920 Jascha Horenstein served as an assistant to Wilhelm Furtwängler in Berlin and began his career conducting the Schubert Choir in Berlin. In 1923 he was a guest conductor with the Wiener Symphoniker. Returning to Berlin, he conducted the Blüthner Concerts (1924) and was conductor of the Berliner Symphoniker (1925-1928); he also appeared as a guest conductor with the Berliner Philharmoniker. He became principal conductor of the Düsseldorf Opera in 1928, and then the company's Generalmusikdirektor in 1929, but was removed from that position in March 1933 by the Nazi regime because he was a Jew. His Düsseldorf tenure was the only permanent musical directorship in his career. After conducting in Europe, Australia, New Zealand, and Palestine, he went to the USA in 1940 and became a naturalized American citizen. He also taught at the New School for Social Research while in New York City.
Following the end of World War II, Jascha Horenstein resumed his career in Europe. He became especially admired in England, where he appeared as a guest conductor with the London Symphony Orchestra. In 1961 he made his debut at London's Covent Garden conducting Fidelio. His final operatic, and British, engagement was his March 1973 performances at the Royal Opera House, Covent Garden of Richard Wagner's Parsifal.
While Jascha Horenstein's repertoire ranged widely from the Baroque era to the 20th century, he is particularly remembered as a champion of modern music and as a Anton Bruckner and Gustav Mahler conductor. In 1929 he conducted the premiere of three movements of Alban Berg's Lyric Suite in an arrangement for string orchestra. In 1950, he conducted the first Paris performance of A. Berg's Wozzeck. Horenstein conducted the works of A. Bruckner and G. Mahler throughout his career, and he also displayed ongoing interest in Carl Nielsen, whom he knew personally, at a time when these composers were unfashionable. For example, his 1952 Vox recording of G. Mahler's Symphony No. 9 was the first studio recording, and the second commercial record, of that work. Several years later, he recorded the original version of Bruckner's Symphony No. 9. He made studio recordings of several of G. Mahler's symphonies at various points in his career, including Symphonies Nos. 1 and 3 with the London Symphony Orchestra. A number of radio archives hold broadcast airchecks of many of the other G. Mahler symphonies, as well as Das Lied von der Erde. In recent years, several of Horenstein's concert performances have been reissued on the BBC Legends label, including his celebrated 1959 Royal Albert Hall performance of G. Mahler's Symphony No. 8 and his 1972 Manchester performance of G. Mahler's Das Lied von der Erde. Horenstein also recorded Robert Simpson's Third Symphony and music by Paul Hindemith and Richard Strauss during the last few years of his life. His opera recordings included Carl Nielsen's Saul og David. He was also the first conductor to record the complete J.S. Bach's Brandenburg Concertos (BWV 1046-1051) on period instruments (Vox, September 1954).