Skip to content

All faculty

Mark Popofsky

Lecturer on Law

2025-2026

Mark Popofsky
Download image

Mark Popofsky is Chair of the Antirust Group at Ropes & Gray LLP. In addition to serving as a Lecturer on Law at Harvard, where he has taught several Antitrust courses, Mark has served as Adjunct Professor of Advanced Antitrust Law and Economics at the Georgetown University Law Center for over 25 years, as a Lecturer in Law for Advanced Antitrust at the U. of Pennsylvania Carey Law School, and as an Adjunct Professor of Advanced Antitrust at the New York University School of Law.  Mark also and has taught Advanced Antitrust, and holds the title of Distinguished Scholar in the Competition Law Center, at the George Washington University Law School.

Mark previously served as Senior Counsel to Assistant Attorney General Joel Klein in the Antitrust Division of the U.S. Department of Justice. While at the DOJ, Mark played a key trial role in United States v. Microsoft Corp., the Department’s landmark monopolization case, and argued United States v. Nippon Paper, which established the criminal extraterritoriality of the Sherman Act, while serving in the Antitrust Division’s Appellate Section. Mark also served as a prosecutor in the U.S. Attorney’s Office in the Eastern District of Virginia.  More recently, in 2020, Mark won a landmark victory in the California Supreme Court in Ixchel Pharma, LLC v. Biogen, Inc., 9 Cal. 5th 1130 (2020), a case at the intersection of antitrust and non-compete law.  For the last several years, Mark has served as trial and then appellate counsel to Google in the United States v. Google, LLC “search monopolization” case (D.D.C. and D.C. Cir.).

Mark’s scholarly work, and practice, centers on exclusionary conduct and the intersection between antirust and intellectual property. His article on legal standards and monopolization doctrine, Defining Exclusionary Conduct: Section 2, The Rule of Reason, and the Unifying Principle Underlying Antitrust Rules, 73 Antitrust L.J. 435 (2006), is widely cited. The Sherman Act’s Criminal Extraterritoriality, Comp. Policy Int’l (2011), won the Burton Prize for legal achievement. Mark has written and spoken widely on the application of the antitrust laws to Patent Assertion Entities and the extraterritorial scope of the Sherman Act. He is a leader and longtime member of the ABA Antitrust Section.

Mark Clerked for Dorothy W. Nelson on the U.S. Court of Appeal for the Ninth Circuit in 1993-94.  He received his J.D. from Harvard Law School in 1993 and his A.B. from Brown University in History and Economics in 1990.

Clerkships

  • Dorothy W. Nelson, U.S. Court of Appeal for the Ninth Circuit, 1993 - 1994