D. Sean Trainor

D. Sean Trainor is a highly experienced patent litigator and the Chair of ITC Litigation within O'Melveny & Myers' Intellectual Property & Technology practice group. Based in Washington, DC, he joined O'Melveny as a partner in January 2017. Trainor’s practice spans a broad array of technologies, including wireless telecommunications protocols, mobile telephone handsets and chipsets, lithium-ion batteries, data storage systems, laser printers, flash memory, semiconductor devices and fabrication, and advanced medical devices. He is particularly noted for his expertise in navigating the unique domestic industry jurisdictional requirements of International Trade Commission (ITC) investigations.

Trainor frequently represents both complainants and respondents in high-stakes patent disputes, often defending technology companies against infringement allegations, particularly before the ITC. His sole tracked district court appearance reflects his role as lead counsel defending Hyundai Motor Company in Mimzi, LLC v. Hyundai Motor Company. His significant case outcomes include obtaining complete victories for respondents in ITC investigations concerning smartphones and tablets (involving seven patents and over 100 claims) and flash memory products (a four-patent case). He also successfully represented complainants in an ITC investigation involving lithium metal oxide cathode materials, leading to a Limited Exclusion Order. Furthermore, Trainor secured summary judgment of noninfringement, affirmed by the Federal Circuit, for a third-party defendant on behalf of the U.S. Postal Service. Notably, he successfully represented a pharmaceutical manufacturer in GSK and Tafas v. Dudas and US Patent and Trademark Office, a case recognized as the US Patent Case of the Year in 2009 by Managing Intellectual Property, where he obtained summary judgment that the PTO’s rules exceeded its agency authority.

While his practice heavily emphasizes ITC and district court litigation, specific details regarding D. Sean Trainor’s experience with Patent Trial and Appeal Board (PTAB) or inter partes review (IPR) proceedings are not explicitly mentioned in available professional profiles.

Trainor is admitted to practice in the District of Columbia and Virginia, and before the U.S. Patent and Trademark Office. He earned his J.D., with honors, from George Washington University in 1998 and holds a B.S. in Mechanical Engineering, with honors, from Michigan State University, received in 1995.