In 1924 Hart was made a Fellow of the Royal College of Music. In 1927 he became acting conductor for the Melbourne Symphony Orchestra (MSO), and in 1928, after the death of Alberto Zelman, the permanent conductor. In 1932 the Melbourne University Conservatorium Orchestra and the MSO amalgamated under the joint conductorship of Hart and Bernard Heinze. In 1929 the MSO was the first Australian orchestra to play open-air concerts. These were in Melbourne's Alexandra Gardens, under the baton of Hart. These 'Popular Concerts' were made possible through a donation by Sidney Myer. Hart was highly regarded as a teacher, his pupils including Peggy Glanville-Hicks, Margaret Sutherland and Robert Hughes.