Beginning his career as a cellist, with a degree from the Hochschule in Stuttgart, Gueller won the United German Radios Conducting Competition in 1979. Two years later he was deputed by the legendary conductor Sergiu Celibidache to take the Stuttgart Radio Symphony Orchestra on a national tour, and was acclaimed as one of Germany's most talented young conductors. Celibidache, who regarded Gueller as his best pupil, also invited him on many occasions to conduct the Munich Philharmonic Orchestra. Today Gueller has an extremely heavy international schedule conducting orchestras throughout the world.

Gueller is increasingly being sought after internationally. In recent times he has been lauded in the prestigious Stuttgarter Zeitung for his direction of the Stuttgart Radio Symphony Orchestra in Bruckner's monumental ninth symphony, in The Australian for his highly successful concerts with the Adelaide Symphony Orchestra and in El Pais for his direction of the City of Barcelona Symphony Orchestra, and his debut in two concerts with the Nashville Symphony Orchestra in America garnered standing ovations, a return invitation to conduct Mahler which was equally well received, and yet further invitations. His direction of the concert version of Elektra with the CTPO and La Traviata in the Spier Summer Festival in South Africa were both highly acclaimed.

Recordings:

Apart from his recordings for national and international broadcast, Bernhard Gueller has made Compact Disc recordings with RSO Stuttgart and Stuttgart Chamber Orchestra. Most recently released CDs are with Peter Lukas Graf (flute) and with oboist Lajos Lensces, both with the RSO Stuttgart (SWR). His CD of Mahler's Kindertotenlieder and Wagner's Wesendoncklieder with mezzo soprano Hanneli Rupert, the CTPO and the Cape Philharmonic Orchestra was released on the RCA label in 2003. He also conducted the CPO in an internationally released film documentary, Cosmic Africa. His first CD with Symphony Nova Scotia, comprising works by internationally-acclaimed Canadian composer Christos Hatzis and featuring violist Rivka Golani, percussionist Beverly Johnson and oboist Suzanne Lemieux, was released in 2006, to great acclaim, notably by the Halifax Chronicle Herald which noted that "The orchestra, superbly directed by Gueller, whose understanding of what Hatzis had in mind went far deeper than the notes, plays compellingly and brilliantly."