He has written over 20 articles on topics ranging from an empirical analysis of judicial decision-making in the patent law to the First Amendment status of software programs. His work has appeared in the Stanford Law Review, Columbia Law Review, and the University of Pennsylvania Law Review, among several others. He is the author (with Professor Craig Nard) of Patent Law: Concepts and Insights (Foundation Press 2008). He is a frequent lecturer on intellectual property topics worldwide.

Prior to joining the Penn Law faculty in 2000, Wagner served as a clerk to Judge Raymond C. Clevenger III of the U.S. Court of Appeals for the Federal Circuit. He holds degrees from Stanford Law School, the University of Michigan, the College of Charleston, and was the 1994-95 Roger M. Jones Fellow at the London School of Economics.