Brian Ashley Rosenthal

Brian Ashley Rosenthal is a highly experienced patent litigation attorney, currently a partner in the New York office of Gibson, Dunn & Crutcher. His practice focuses heavily on defending clients in complex patent disputes across a wide array of technologies, with particular concentrations in computer software, electronics, and medical devices. He also has significant experience with networking, wireless technologies (including 5G), cloud computing, targeted advertising, and multi-factor authentication.

Rosenthal primarily represents operating companies as a defendant, having appeared exclusively on the defendant side in all six tracked cases. He has a strong track record as lead counsel in over 125 patent cases, handling all litigation aspects from complaint through trial and appeal. Before joining Gibson Dunn, he was also associated with Fish & Richardson and Kellogg, Hansen, Todd, Figel & Frederick, where he similarly represented defendants in patent matters.

His notable successes include securing a complete defense verdict for Cisco Systems Inc. in a $50 million patent infringement lawsuit involving computer networking patents, which is believed to be the first known jury verdict on the prior use defense under 35 U.S.C. § 273(a) in the United States. He also obtained a rare directed verdict for Cisco in a $121 million communications network patent case and another defense verdict for Cisco and Duo Security in a multi-factor authentication patent dispute. Further, Rosenthal has achieved victories for clients like Plaid (motion to dismiss for patent ineligibility), Google and Motorola (invalidating patents via IPR and winning Federal Circuit appeal), Dell EMC (dismissal of all eight asserted networking patents), and Philips (dismissal in District Court and winning Federal Circuit appeal). He also successfully represented Acushnet in a six-year litigation, invalidating four golf ball patents through inter partes reexaminations and winning two jury trials.

Rosenthal has substantial experience with Patent Office validity proceedings, including inter partes review (IPR) and post-grant review (PGR) petitions, often managing these in parallel with high-stakes litigation. He earned his Juris Doctor from Cornell University in 2000 and a Bachelor of Science in Computer Science from the University of Western Ontario in 1997. He is admitted to the New York Bar (2001) and the District of Columbia Bar.