Denis Sullivan

Denis co-leads Barclay Damon’s Intellectual Property Practice Group. His national patent practice combines infringement litigation with advice on managing and optimizing patent portfolios in the United States and internationally. He handles patent disputes in federal district court and proceedings before the patent office, including inter partes reviews and reexaminations.

Denis’s background as a licensed professional electrical engineer informs his work on technically complex patent matters across a range of industries. In one dispute involving several high-tech patents, he represented a mid-sized company sued for infringement by a much larger competitor. He developed and carried out litigation strategies grounded in his understanding of the technology, and the competitor dropped the lawsuit early in the case.

His portfolio work focuses on helping clients make strategic decisions about their patents alongside the demands of protecting, defending and monetizing their innovations. Denis brings an understanding of technical issues and business needs to that work, as well as to patent office proceedings and infringement litigation.

Denis began his legal career in the IP Litigation Department of Kirkland & Ellis in New York City. He later moved to an intellectual property boutique in Central New York, where he served as managing partner, before bringing his practice to Barclay Damon. He graduated first in his class in electrical engineering and, while working as an engineer, attended law school at night and again graduated first in his class.

• New York Law School, JD, Summa Cum Laude (Class Rank: 1), New York Law School Law Review
• Manhattan College, BS, Summa Cum Laude (Class Rank: 1), General Excellence Award in Electrical Engineering

• American Intellectual Property Law Association
• Intellectual Property and Innovation American Inn of Court
• New York State Licensed Professional Engineer

• Managing Intellectual Property Magazine: "Barclay Damon Boosts IP Group After Burns & Levinson Closure"
• Daily Record, "Barclay Damon Adds Three Lawyers From Murtha Cullina LLP"
• Law360, “Strategies for Avoiding Institution of an IPR”

• Practicing Law Institute’s 11th Annual Patent Law Institute, “The Patent Trial and Appeal Board Turns Five”
• IP Counsel Exchange, “PTAB Litigation Crash Course: A Litigator’s Guide to Obtaining Successful Results at the PTAB”
• Rochester Intellectual Property Law Association, “Escaping From Wonderland: An Analysis of Decisions Where Patent Claims Have Survived Section 101 Challenges Under Alice Corp. v. CLS Bank”
• Practicing Law Institute’s Ninth Annual Patent Law Institute, "Inter Partes Review and Post-Grant Review: Interplay of PTAB/District Court Litigation"