Osterhammel started his academic career as a research fee student at the London School of Economics in 1976/77 and studied and worked there under Professor Ian Nish. In 1980 he obtained his Ph.D. from the University of Kassel (Germany) in modern history. Two years later he started as a fellow at the German Historical Institute in London. Between 1986 and 1990 he was a senior lecturer in political science at the University of Freiburg (Germany). He then worked for seven years as professor of modern history at the "FernUniversität Hagen", a distance-learning university in Germany. He has also worked as a professor of modern history at the Graduate Institute of International Studies in Geneva and the in the same position in the University of Konstanz (Germany) in 1999. In 2001-2002 he was a fellow at the "Netherlands Institute for Advanced Study" in the Humanities and Social Sciences. In 2014 he was elected a Corresponding Fellow of the "British Academy".