Hannay is a partner in the Chicago-based law firm of Schiff Hardin & Waite, where he concentrates his practice in litigation and counseling in the area of antitrust and trade regulation law. He is an Adjunct Professor at Chicago-Kent law school, teaching courses in antitrust law, intellectual property law, and international law, and is a past chairman of the Chicago Bar Association's antitrust law committee.

Mr. Hannay is active in the American Bar Association, having served as Chair of the Section of International Law & Practice in 1998 through 1999, Chair of the Africa Law Initiative Council from 2000 to 2002, as a member of the House of Delegates, and as a committee officer in the Section of Antitrust law. He has written and lectured widely about antitrust law and is the author or co-author several books.

Before joining Schiff Hardin & Waite, Mr. Hannay served as an Assistant District Attorney under Robert M. Morgenthau in New York City, and prior to that, as a law clerk to Justice Tom Clark of the United States Supreme Court and Judge Myron H. Bright of the United States Court of Appeals for the Eighth Circuit. He graduated from Yale University in 1966 and Georgetown University Law Center in 1973. He is a Vietnam veteran and resides in Barrington Hills, Illinois, with his wife and three children.