Osborne held academic positions in Australia, the United Kingdom, the United States and Singapore. Osborne's main historical contribution had been to synthesize the history of the region as a whole, rather than concentrate on the histories of the present-day nations. Osborne's Southeast Asia association began in 1959 with an Australian diplomatic posting to
Phnom Penh. In 1980 and 1981 Osborne advised the
United Nations High Commissioner for Refugees on the Cambodian refugee problem. In 1982 he returned to Australia, working as Head of the Asia Branch of the
Office of National Assessments, also serving for a year as Head of Current Intelligence. Osborne now lives in Sydney and continues to write while consulting on Asian issues, as well as having been a series editor on the
Short History of Asia Series published by Allen and Unwin. ==Honours==