John has represented many companies in significant, complex litigations involving patents in a variety of fields. He also has an extensive practice in patent counseling, opinion work, inter partes proceedings, and licensing and has been responsible for supervising the patent prosecution of several major corporations.
John has also been active in public service and pro bono work. In 1997, Governor George E. Pataki appointed him to the New York State Task Force on Life and the Law, where he continues to serve. He was an adjunct professor of law at Fordham University from 1989 to 1993 and at Hofstra University from 1986 to 1989. He is a past president of the New York Intellectual Property Law Association.