 Between 1983 and 1999 he served in various capacities, among them as senior economic affairs officer in the International Trade Division, chief of the Policy Clearance Unit, advisor in the office of the secretary-general and executive assistant to the deputy secretary-general.After obtaining a bachelor's degree in languages and economics from the University of Malta in 1965, Bonello pursued his studies as a Rhodes Scholar at the University of Oxford, where he took an honours degree in philosophy, politics and economics in 1969.In 1969 he joined the Central Bank of Malta as a research assistant and later served as senior research officer from 1971 to 1978.