Dimitris Mitropoulos directed the Berlin Philharmonic while participating as a soloist in Prokofiev's Third Piano Concerto. He had previously collaborated with the Berlin State Opera from 1922 to 1924, where he worked as a music tutor. He met Italian composer and pianist Ferruccio Busoni, who played a decisive role in his development as a musician. In 1924 he returned to Athens and assumed the conductor position at the Symphony Orchestra of the Athens Conservatory (1924-1925 and 1927-1937) and the Orchestra of the Concert Association (1925-1927). At the same time, he pursued an international career, directing famous European musical ensembles. In 1936 he visited the US for the first time to conduct the Boston Symphony Orchestra at the invitation of the orchestra's permanent conductor, Serge Koussevitzky. In 1938 he became the Minneapolis Symphony Orchestra's conductor, where he remained until 1949 and elevated it to one of the leading orchestras in the United States. In 1949 he moved to the New York Philharmonic, where he remained until 1957 at the beginning as co-conductor and later as conductor and music director.