Bruno Walter (September 15, 1876 – February 17, 1962) was a German-born conductor and composer. He was born in Berlin, but moved to several countries between 1933 and 1939, finally settling in the United States in 1939. His original name was Bruno Schlesinger, but he began using Walter as surname in 1896. The family name Schlesinger was officially dropped in 1911, when he took up Austrian citizenship.

Born near Alexanderplatz in Berlin to a middle-class Jewish family, Bruno Walter began his musical education at the Stern Conservatory at the age of eight, making his first public appearance as a pianist when he was nine. However, following visits to one of Hans von Bülow's concerts in 1889 and to Bayreuth in 1891, Walter changed his mind and decided upon a conducting career. He made his conducting début at the Cologne Opera with Lortzing's Waffenschmied in 1894. Later that year he left for the Hamburg Opera to work as a chorus director, where he first met and worked with Gustav Mahler, whom he idolized and with whose music he would later be strongly identified.

In 1896 Walter took a conducting position at the opera house in Breslau—a job found for him by Mahler. This was where Walter started to drop his surname "Schlesinger", at the request of either Mahler or the director, in order to make his name sound less Jewish. In 1897, he took an opera-conducting position at Pressburg, and in 1898 he took one in Riga. Then Walter returned in 1900 to Berlin, where he assumed the post of Royal Prussian Conductor at the Berlin Royal Opera House, succeeding Schalk; his colleagues there included Richard Strauss and Karl Muck. While at Berlin he also conducted the Berlin premiere of Der arme Heinrich by Hans Pfitzner, a composer who would become a lifelong friend of his.

In 1901 Walter accepted Mahler's invitation to be his assistant at the Court Opera in Vienna. Walter led Verdi's Aida at his debut. In the following years Walter's conducting reputation soared as he was invited to conduct throughout Europe -- in Prague, London (where in 1910 he conducted Tristan und Isolde and Ethel Smyth's The Wreckers at Covent Garden) and in Rome. A few months after Mahler's death in 1911, Walter led the first performance of Das Lied von der Erde in Munich, as well as Mahler's Ninth Symphony in Vienna the next year.

Although Walter became an Austrian citizen in 1911, he left Vienna to become the Royal Bavarian Music Director in Munich in 1913. In January the next year Walter conducted his first concert in Moscow. During the First World War, he remained actively involved in conducting, giving premieres to Erich Wolfgang Korngold's Violanta and Der Ring des Polykrates as well as Pfitzner's Palestrina.

Walter ended his appointment in Munich in 1922, and left for New York, the United States in 1923, working with the New York Symphony Orchestra in Carnegie Hall; he later conducted in Detroit, Minnesota and Boston.

Back in Europe Walter was re-engaged for several appointments, including Berlin (1925, as musical director at the Städtische Opera, Charlottenburg) and Leipzig (1929). He made his debut at La Scala in 1926. In London, Walter was chief conductor of the German seasons at Covent Garden from 1924 to 1931.

In 1933, when the Nazi party began to bar his musical appointments in Germany, Walter left for Austria. Austria would remain the main center of activity for the next several years, although he was also a frequent guest conductor of the Amsterdam Concertgebouw Orchestra from 1934 to 1939, and made guest appearances such as in annual concerts with the New York Philharmonic from 1932 to 1936. When Hitler annexed Austria in 1938, France offered Walter citizenship, which he accepted; however, in November 1, 1939, he eventually set sail for the United States, which became his permanent home. Beverly Hills remained Walter's residence for many years, and his many expatriate neighbors include the German writer Thomas Mann.

While Walter had many influences within music, in his Of Music and Making he notes a profound influence from the philosopher Rudolf Steiner. He notes, "In old age I have had the good fortune to be initiated into the world of anthroposophy and during the past few years to make a profound study of the teachings of Rudolf Steiner. Here we see alive and in operation that deliverance of which Hoelderlin speaks; its blessing has flowed over me, and so this book is the confession of belief in anthroposophy. There is no part of I my inward life that has not had new light shed upon it, or been stimulated, by the lofty teachings of Rudolf Steiner ... I am profoundly grateful for having been so boundlessly enriched ... It is glorious to become a learner again at my time of life. I have a sense of the rejuvenation of my whole being which gives strength and renewal to my musicianship, even to my music-making."

During his years in the United States, Walter worked with many famous American orchestras, including the Chicago Symphony Orchestra, the Los Angeles Philharmonic, the NBC Symphony Orchestra, the New York Philharmonic Orchestra (where he was musical adviser from 1947 to 1949), and the Philadelphia Orchestra. From 1946 onwards, he made numerous trips back to Europe, becoming an important musical figure in the early years of the Edinburgh Festival and in Salzburg, Vienna and Munich. His late life was marked by stereo recordings with the Columbia Symphony Orchestra. He made his last live concert appearance on December 4, 1960 with the Los Angeles Philharmonic and pianist Van Cliburn. His last recording was a series of Mozart overtures with the Columbia Symphony Orchestra at the end of March in 1961.

Bruno Walter died of a heart attack in his Beverly Hills home in 1962.