During the Second World War he served as Music Advisor, Northern Command (1941–1945), ENSA. Following the war, he became a Professor of the Royal College of Music, from 1946 to 1976, and was also the college's Director of Opera from 1955 to 1976, when he retired. Concurrently, Austin served as Music Director to the New Era Concert Society (1947–1957) and was a guest conductor at Sadler's Wells Theatre, with other London and provincial orchestras in the UK, and overseas in the Netherlands, Belgium, Germany, Spain, Sweden, Switzerland, Finland, Yugoslavia, Czechoslovakia, Cuba, Mexico, South Africa, the United States, and also in South America. Austin recorded a selection of works by Balfour Gardiner in May 1955 for Argo, with Alexander Young, the Goldsmiths’ Choral Union and the London Symphony Orchestra (Overture to a Comedy, Shepherd Fennel’s Dance, April, Philomela). Later that year with cellist André Navarra he set down recordings of Bloch's Schelomo and Tchaikovsky's Variations on a Rococo Theme Op.30 for Parlophone. A recording of "The Beggar's Opera" featured Dennis Noble, Carmen Prietto, Martha Lipton, Roderick Jones, Marjorie Westbury, John Cameron and William McAlpine.