From 1929 to 1931 he was a research fellow of the
Rockefeller Foundation, and admitted to the prestigious
Keynes Club. His work won him the
Adam Smith Prize in 1932. In 1931 he was appointed Lecturer in Economics at the
University of Edinburgh. He was in 1937 appointed Professor of Economics at
Swansea University, being highly commended by
John Maynard Keynes, then at King's College, Cambridge, and by
D. H. Robertson, of Trinity College, Cambridge. He was appointed to the Chair of Economics,
University of Adelaide, in November 1938. In 1942 he was seconded to the wartime Commonwealth Rationing Commission as an economic adviser, and appointed temporary lieutenant-colonel in the Australian Army to provide economic advice. He was a member with
Sidney Crawford and half-a-dozen diverse people of influence in the liberal South Australian
think tank "
Common Cause", which discussed post-war reconstruction. In 1945 he left Adelaide for Belfast, where he had been appointed Professor of Economics, and Dean of the Faculty of Economics at
Queen's University, Belfast. He was appointed Vice-Chancellor of the
University of Tasmania in November 1956, succeeding the ineffectual
Torleiv Hytten, and served from 1 July 1957 to 31 December 1967. Isles was the first full time Vice-Chancellor of the University.
Sydney Sparkes Orr, who had been appointed, on the basis of falsified documents, Professor of Philosophy, University of Tasmania, in 1952 was sacked in 1955 for allegedly having sexual relations with a female undergraduate student, a celebrated and controversial case at the time. Orr sued for wrongful dismissal, and after having lost, appealed. Orr had a great number of supporters, and a great deal was published on both sides of the argument. In an effort to clear the air, though having had no part in the sacking, Isles published a leaflet entitled
Dismissal of Sydney Sparkes Orr by the University of Tasmania setting out the University's case, and was in 1961 sued by Orr for defamation, claiming £50,000 in damages as he had been unable to find employment for five years. Isles established new faculties at the University of Tasmania, including the Faculty of Agriculture and School of Medicine, both identified as being important for the growth of the University. ==Recognition==