Since 2003 he has taught at Indiana University in the Department of History and the Department of East Asian Languages & Cultures. He is also an affiliate member of the Institute for International Strategy, School of Liberal International Affairs, Waseda University, Tokyo Japan.
His research interests include the history of social science, consumption and mass consumer culture, environmental history, urban history, and peace history. He has written about twentieth-century forms of statistical knowledge within political-economics and about the rise of the idea of limits in economic and environmental thought.
O'Bryan published The Growth Idea: Purpose and Prosperity in Postwar Japan (A Study of the Weatherhead East Asian Institute, Columbia University) University of Hawaii Press in 2009. The work is a conceptual history of growth as an object of social science knowledge during the mid-twentieth century and as a new analytical paradigm that came to govern the terms by which Japanese understood their national purposes and practiced their socio-economic policies. At heart, the book is an intellectual history of the growthist ideal, one that emerged in Japan after the demise of empire. His next major project, Dreams of the Archipelago, is an environmental, urban, and cultural history that narrates a variety of schemes to reshape the built environments and human geographies of late twentieth-century Japan. It traces a history of Japan as both an icon of Cold War developmentalism and as the place in the closing decades of the century in which new fears of a more limited human future were perhaps most acutely expressed.