The eminent Austrian conductor, Clemens (Heinrich) Krauss, was born in Vienna, the out-of-wedlock child of Clementine Krauss, then a 15-year-old dancer in the Vienna Imperial Opera Ballet, later a leading actress and operetta singer, who was a niece of the prominent 19th-century operatic soprano, (Marie) Gabrielle Krauss (1842-1904). His natural father, the chevalier Hector Baltazzi (1851-1916), belonged to a family of wealthy Phanariot bankers resident in Vienna. Baltazzi's older sister Helene was married to Baron Albin Vetsera and was the mother of Baroness Mary Vetsera, who was thus Clemens Krauss' first cousin. As a boy, Krauss was a chorister in the Hofkapelle (Imperial Choir) (Wiener Sängerknaben). He attended the Vienna Conservatory, graduating in 1912. He studied piano with Reinhold, composition with Hermann Graedener and theory with Richard Heuberger.
After graduation, Clemens Krauss was a chorus master at the Brunn Theater (1912-1913), making his conducting debut there with a performance of Zar und Zimmermann (January 13, 1913). Krauss made the rounds of regional centers, serving as 2nd conductor at Riga's German Theater (1913-1914) and in Nuremberg (1915-1916), and as 1st conductor in Stettin (now known as Szczecin) (1916-1921). The latter appointment gave him ample opportunity to travel to Berlin to hear Arthur Nikisch conduct the Berliner Philharmoniker, a major influence. Krauss's next post was back in Austria, where he became director of the opera and symphony concerts in Graz (1921-1922).
In 1922 Clemens Krauss became Franz Schalk's assistant at the Wiener Staatsoper; he also taught conducting at the Vienna Academy of Music (1922-1924) and was conductor of the Vienna Tonkünstlerkonzerte (1923-1927). He was director of the Frankfurt am Main Opera and its Museumgesellschaft concerts (1924-1929). Then he was director of the Wiener Staatsoper (1929-1934). Its orchestra, in its independent concert form as the Wiener Philharmoniker, appointed him its music director in 1930. In 1926 he made his first appearance at the Salzburg Festivals, and returned there regularly (1929-1934). In 1930 he conducted Alban Berg's Wozzeck. he also conducted in South America in 1927, and in 1929 visited the USA in 1929, as a guest conductor with the New York Philharmonic Orchestra and Philadelphia Orchestra. He made his debut at London's Covent Garden in 1934.
In 1933 and 1934 Clemens Krauss gave up his Vienna positions, becoming director of the Berlin State Opera (1934-1937), after Erich Kleiber resigned in protest over Nazi rule. In 1933 he took over the preparations for the premieres of Strauss's Arabella when the conductor Fritz Busch (another non-Jewish anti-Nazi) left. Krauss's own position on Nazism was unclear, although he enjoyed a close relationship with Nazi official Alfred Frauenfeld and it has been claimed that he sought Nazi Party membership in 1933. In 1937 he was appointed Generalmusikdirektor of the Bavarian State Opera in Munich, following the resignation there of Hans Knappertsbusch. From 1939 to 1944 he also taught at the Mozarteum University of Salzburg where among his pupils was composer Roman Toi. After the Munich opera house was bombed in 1944, shutting it down, Clemens Krauss returned to conduct the Wiener Philharmoniker until it closed shortly before the end of World War II (1944-1945).
Having been a friend of Hitler and Göring, and a prominent figure in the musical life of the Third Reich, Clemens Krauss was held accountable for his actions by the Allied authorities after the end of World War II. There was a strain of humanity in Krauss, however, for he had assisted Jews to escape the clutches of the barbarous Führer's fury. In 1947 he was permitted to resume his career with appearances at the Wiener Staatsoper; he took it to London that same year. He was a conductor with the Wiener Philharmoniker from 1947, and also served as conductor of its famous New Year's Day Concerts. From 1951 to 1953 he conducted at London's Covent Garden, and in 1953-1954 at the Bayreuth Festivals.
Clemens Krauss died during a visit to Mexico City. He was married to famous Romanian soprano Viorica Ursuleac (his second wife), who often appeared in operas under his direction; he also accompanied her in recitals. He is now buried along with his wife, who died in 1985, in Ehrwald, Austria. He was a close friend and collaborator of Richard Strauss, who considered him one of the finest interpreters of his works. He conducted the premieres of R. Straussí operas Arabella (Staatsoper Dresden, July 1, 1933), Friedenstag (Nationaltheater, Munich, July 24, 1939), Capriccio, for which he wrote the libretto (Bayerische Staatsoper, Munich, October 28, 1942), and Die Liebe der Danae (Festpielhaus, Salzburg, August 16, 1944). Krauss was also renowned as a conductor of works by Mozart, Wagner, and Verdi, as well as those by the Viennese waltz composers.
Clemens Krauss did not make many recordings; but his 1950 performance of Johann Strauss II's Die Fledermaus, made in Vienna, is still regarded by some as the best one. His 1953 live performance of Richard Wagner's Der Ring des Nibelungen from Bayreuth is highly regarded. A performance with the Wiener Symphoniker of L.v. Beethoven's Choral Fantasy, reissued on more than one inexpensive label since its original appearance on Vox Records, is also one of the few recordings featuring pianist Friedrich Wührer available on compact disc.