After the end of the war, the American military administration offers him leading management positions at the opera and radio; Hartmann rejects these, however, and he takes over the function of a musical dramaturge at the Bavarian State Opera

Hartmann realizes a matinee series dedicated to “den fortschrittlichen und neuzeitlichen Strömungen der Musik” [the progressive and modern currents in music, KAH]; beginning of the later musica viva, one of the most successful concert series for new music to date