Morgenstern grew up in Vienna, Austria, where he also went to university. In 1925, he graduated from the University of Vienna and got his PhD in political science. From 1925 until 1928, he went on a three-year fellowship financed by the Rockefeller Foundation. After his return in 1928, he became a professor in economics at the University of Vienna until his visit to Princeton University in 1938. In 1935, Morgenstern published the article Perfect Foresight and Economic Equilibrium, after which his colleague Eduard Čech pointed him to an article of John von Neumann, Zur Theorie der Gesellschaftsspiele (1928).
During Morgenstern's visit to Princeton University, Adolf Hitler took over Vienna through the Anschluss Österreichs and Morgenstern decided to remain in the United States. He became a member of the faculty at Princeton but gravitated toward the Institute for Advanced Study. There, he met von Neumann and they collaborated to write Theory of Games and Economic Behavior, published in 1944, which is recognized as the first book on game theory. Game theory is a mathematical framework for the study of strategic structures which govern rational decision-making in certain economic, political and military situations. In 2013, the University of Vienna relocated the Faculty of Business, Economics and Statistics and named the square Oskar-Morgenstern-Platz in his honor.
The collaboration between economist Morgenstern and mathematician von Neumann led to the birth of entirely new areas of investigation in both mathematics and economics. These have attracted widespread academic and practical interest since that time. In 1944, Morgenstern also became a United States citizen, and four years later he married Dorothy Young, with whom he had two children, Carl and Karen. In 1950, he was elected as a Fellow of the American Statistical Association. Morgenstern remained at Princeton as a professor of economics until his retirement in 1970, at which time he joined the faculty of New York University. Morgenstern wrote many other articles and books, including On the Accuracy of Economic Observations, and Predictability of Stock Market Prices with subsequent Nobel laureate Clive Granger.
^S.L.A. Marshall (November 22, 1959). "While the Atomic Clock Ticks On – The Question Of National Defense". NYTimes.com. 306 pp. New York: Random House. "In this book, Oskar Morgenstern, the Princeton economist, takes a look at the prospects for American survival and what we are doing to improve them. What he finds should make the angels weep."