Humphreys teaches at Harvard where he works on comparative problems in the history of capitalism, philanthropy and social reform. He received his PhD from NYU and studied in Paris as a Fulbright scholar at the École des Hautes Études en Sciences Sociales and as a pensionnaire étranger at the École Normale Supérieure. Humphreys previously taught European history and politics at Princeton University and served as associate fellow at the Rutgers Center for Historical Analysis, scholar-in- residence at the Rockefeller Archive Center, and as visiting research associate at the Johns Hopkins School of Advanced International Studies. He is currently also a senior associate at Tellus Institute in Boston, where he directs the Center for Social Philanthropy.
