In 1945, along with Richard Goldner, Dullo co-founded Musica Viva Australia, which had its first concert on 8 December 1945, and went on to become the world's largest chamber music organisation. The inaugural concert included Dullo's arrangement for string orchestra of Mozart's Fantasy No. 1 in F minor for Mechanical Organ.[3]
He was also vice-president of the Sydney Mozart Society and correspondent of the Salzburg Mozarteum.[1]
In the 1960s he reconstructed and completed five piano sonatas by Franz Schubert.[4][5] These have been recorded by Romola Costantino and Geoffrey Saba. He also wrote cadenzas for Mozart piano concertos, and wrote program notes for the ABC, Musica Viva and the Mozart Society, and articles for music publications.[1]
Along with Trevor Jarvie and others, Dullo founded Australia's first FM radio station, 2MBS (now called Fine Music 102.5), which began broadcasting on 15 December 1974. He helped devise programs, and lent the station many records from his extensive private collection.[4]
In 1977 he was appointed to the Order of Merit of the Federal Republic of Germany.[1]
Walter Andreas Dullo collapsed at the offices of 2MBS on 22 August 1978,[4] and died at the Royal North Shore Hospital in Sydney, aged 75.[1]