From 1991 to 2004, Macey was J. DuPratt White Professor of Law, Director of the John M. Olin Program in Law and Economics at Cornell Law School, and Professor of Law and Business at Cornell University's Johnson Graduate School of Business.
Macey has taught at major universities throughout the world, including Bocconi University (Milan), the University of Tokyo; the University of Toronto; the University of Turin, the University of Amsterdam Department of Finance, and the Stockholm School of Economics, Department of Law.