From 1969 until 1972 Eri Klas assisted Boris Haikin at the Bolshoi Theatre in Moscow. Here, for twelve years, he conducted both opera and ballet with world-famous singers and dancers and went on tours to Paris, Tokyo and Athens. In 1975 he was named Music Director of the Estonian National Opera; he has since become conductor laureate. From 1985 until 1990 Eri Klas was Artistic Director at the Swedish Royal Opera, since 1990 a regularly returning guest-conductor at the Finnish National Opera as well as at the Hamburg Opera. From 1991 until 1996 he was Chief Conductor of the Aarhus Symphony Orchestra in Denmark. In September 1996 he was appointed Chief Conductor of the Netherlands Radio Symphony Orchestra. Also, since August 1998, he is Chief Conductor of the Tampere Philharmonic Orchestra.

In 1991 Eri Klas made his début in the United States, with the Los Angeles Philharmonic Orchestra. Since then he returns annually to conduct most of the major U.S. orchestras, such as the Chicago Symphony Orchestra, the Cleveland Orchestra, the symphony orchestras of Cincinnati, Indianapolis, Atlanta and St.Louis, as well as the orchestras of Seattle, Detroit, Dallas, Vancouver and Minnesota. Eri Klas is a passionate champion of the music of his native Estonia, notably the music of Pärt, Tubin and Eller. One of the composers with whom he feels a particularly strong bond is Alfred Schnittke. In 1986 he collaborated with Natalia Gutman and the Munich Phiharmonic Orchestra in the world première of Schnittke’s first cello concerto. In addition, he conducted the 1989 world première of his ballet “Per Gynt”, with the Hamburg Opera. Eri Klas has a recording contract with the Scandinavian BIS Record label and with Ondine. His recording, with the Tampere Phiharmonic Orchestra, of Einar Englund’s symphonies nrs. 4 and 5 and of “the Great Wall of China” received a Cannes Classical Award in 2002. He recorded the following works of Schnittke: the third symphony, with the Stockholm Philharmonic Orchstra; the ballet music “Per Gynt”, with the Royal Opera Orchestra of Stockholm and the four violin concertos, with the Malmö Symphony Orchestra. In addition, he recorded works of Sibelius with the Finnish National Orchestra; he also recorded with the Lahti Symphony Orchestra and with the Estonian National Opera Orchestra.