Born in Berlin on September 15, 1876, Bruno Walter began his musical education at the age of eight at the Stern Conservatory. When he was nine, he made his first public appearance as a pianist. Following visits to one of Hans von Bulow's concerts in 1889 and to Bayreuth in 1891, Walter decided upon a conducting career. He was first engaged as a coach at the Cologne Opera in 1893, and made his conducting debut there with Lortzing's Waffenschmied. The following year he went to the Hamburg Opera where he worked as an assistant to Gustav Mahler. After seasons at the theatres in Breslau, Pressburg and Riga, he returned in 1900 to Berlin, where he conducted the Berlin premiere of Der arme Heinrich by Hans Pfitzner, whose operas Walter faithfully supported.

In 1901 Walter joined Gustav Mahler at the Court Opera in Vienna. In the following years, which were formative ones for Walter's international career, he was invited to conduct in Prague, London (where in 1910 he conducted Tristan und Isolde and Ethel Smyth's The Wreckers at Covent Garden) and Rome. A few months following Mahler's death in 1911, Walter led the first performance of Das Lied von der Erde in Munich, and in Vienna the following year the first performance of the Ninth Symphony, having also prepared the score for publication. Walter became an Austrian citizen in 1911, officially changing his last name from Schlesinger to Walter. In 1913 he left Vienna to become musical director of the Munich Opera, remaining there until the end of 1922. In 1923 he visited the United States to conduct the New York Symphony Orchestra, and was re-engaged for the following season. Further guest appearances in Europe included several with the Amsterdam Concertgebouw Orchestra. In London, Walter was chief conductor of the German seasons at Covent Garden from 1924 to 1931. In 1925 he returned to Berlin as musical director at the Stadtische Oper, Charlottenburg, and also began his long association with the Salzburg Festival. In 1929 Walter left Berlin for Leipzig to succeed Wilhelm Furtwangler as director of the Gewandhaus concerts.

In 1933, when the political situation became impossible for him, Walter left Germany for Austria. This was to be his 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 elsewhere, including annual visits with the New York Philharmonic from 1932 to 1936, and in Florence in 1936. At the Vienna Staatsoper he was guest conductor from 1935 and artistic adviser from 1936. In 1938 the Anschluss uprooted him once more. Walter was granted French citizenship, but settled in 1939 in the United States. During his American years he conducted the Chicago Symphony Orchestra, the Los Angeles Philharmonic, the NBC Symphony Orchestra, the New York Philharmonic (where he was musical adviser from 1947 to 1949), and the Philadelphia Orchestra, among others. Between 1941 and 1959 he also conducted at the Metropolitan Opera. Beginning in 1947, he made numerous return visits to Europe, becoming an important figure in the early years of the Edinburgh Festival, and returning to Salzburg, Vienna and Munich.

Walter's Mahler recordings contributed to the eventual, if somewhat late, acceptance of the composer, while a generation of opera-goers was treated to his performances of Wagner and Strauss. Walter was also a very capable pianist who occasionally conducted Mozart concertos from the keyboard and accompanied lieder singers including Kathleen Ferrier. His compositions, mostly dating from the first decade of this century, include two symphonies, a symphonic fantasia, some choral works, chamber music and songs.

Bruno Walter died on February 17, 1962, in Beverly Hills, California.