Dr. Keusch is a graduate of Columbia College (AB 1958) and Harvard Medical School (MD 1963). He is trained and board certified in internal medicine and infectious diseases. His professional career has centered around research on global health problems, professional training, and clinical work. He was a member of the Department of Medicine at Mt. Sinai Hospital and Medical School from 1970-1978, where he initiated programs in the pathogenesis of bacillary dysentery and in the relationship between malnutrition and infection, working collaboratively with the Institute of Nutrition of Central America and Panama. In 1979, he joined the Department of Medicine at Tufts-New England Medical Center to start a Division of Geographic Medicine under the "Great Neglected Diseases of Mankind" program at the Rockefeller Foundation. He subsequently became Chief of the Division of Infectious Diseases at Tufts, integrating the clinical and research programs with a focus on global health, and expanding his work to diarrheal disease in India and Bangladesh and initiating work on the AIDS wasting syndrome in Kinshasa, Zaire. Dr. Keusch is the author of over 300 original publications, reviews, and book chapters, and is the editor of 8 books on global health issues.

In 1998, Dr. Keusch was recruited to the National Institutes of Health as Associate Director for International Research and Director of the Fogarty International Center (FIC). During his tenure at NIH, international programs increased dramatically across the NIH in scope and funding. This was especially true at FIC, where 19 new research and training programs were initiated to address global disparities in health while the broadening support from primarily infectious diseases to chronic diseases, including tobacco, mental health, and cognitive function, and cross-cutting issues such as ethics, stigma, brain drain, the communication of health and science information to the public, and the impact of the system of intellectual property rights on health in developing countries. New programs were also created to promote global health research careers of U.S. students in the health professions, including a one year mentored clinical research training program for medical and public health students and a career development award in international research for post-doctoral fellows.

Most recently, Dr. Keusch has joined Boston University as Provost and Associate Dean for Global Health, to help broaden and expand ongoing programs in global health across the university campus. New research and training initiatives are being planned for the university medical and main campus, including programs aimed at Boston University undergraduates with an interest in international studies or development, or in the health professions. Dr. Keusch continues to be involved in Foundation programs such as the Gates Foundation Grand Challenges in Global Health, as well as with the Rockefeller Foundation and Burroughs Wellcome Fund, and multi-national organizations such as the World Health Organization.