He has also been Guest Conductor in the United States, Canada, Australia and New Zealand, working with orchestras such as the Chicago Symphony Orchestra, Philadelphia Orchestra, Cincinnati Symphony Orchestra and the Indianapolis Symphony Orchestra, among many U.S: Orchestras. In his role as Opera conductor, he has been invited to conduct in Hamburg, Vienna, Zürich, Brussels, Weimar, etc.

In 2000 he made his debut with great success in United Kingdom with the Royal Scottish National Orchestra, in the concert series “Scottish Proms” of Glasgow. Shortly after he was Guest Conductor of the Rio de Janerio Opera House Orchestra, Sao Paulo Symphony Orchestra, Mozarteumorchester Salzburg and Jeunesse Musicales World Orchestra.

From 1987 to 1991 he was Principal Conductor of the Hamburger Symphoniker, and from 1991 to 1995 he was Musical and Principal Conductor of the Stuttgarter Philharmoniker. In 1996 he was named Musical Director of the Opera House and Philharmonica Orchestra of Dessau, Germany. In 2000 he was named Principal Conductor of the Tonkünstlerorchester of Vienna and Principal Conductor of the Grant Park Symphony Orchestra and Chicago’s choir. From 2011 to 2016 he was Principal Conductor and Artistic Director of the Orquesta y Coro de RTVE in Spain.
Carlos Kalmar has recorded with various orchestras for different labels such as Cedille Records or Hyperion. He has recorded pieces by Szymanowski, Martinu, Bartok, Joachim or Brahms.