People default image

D. Sean Trainor

Partner
Co-Head of US International Trade Commission practice
Washington, DC
About

D. Sean Trainor is a seasoned intellectual property litigator who represents companies in complex patent and intellectual property disputes, with particular experience in investigations before the United States International Trade Commission (ITC) under Section 337 of the Tariff Act.

Sean’s practice spans the full range of patent litigation, from case strategy and discovery through claim construction, dispositive motions, trial, and appeal. He has extensive experience litigating matters involving sophisticated technologies, including wireless telecommunications protocols, mobile handsets and chipsets, wearable devices, battery technology, flash memory, semiconductor devices and fabrication, advanced medical devices, laser diodes, and light-emitting devices.

Sean has represented parties in significant ITC technology disputes, securing favorable outcomes that have included exclusion orders and complete victories in multi-patent investigations. He has served as counsel in more than 20 trials at the ITC. He also has significant experience before the Exclusion Order Enforcement Branch of US Customs and Border Protection.

Sean has been consistently recognized by leading legal publications for his intellectual property and international trade practice. He has been recognized by Chambers USA for International Trade: Intellectual Property (Section 337), recommended by The Legal 500 US for patent litigation before the ITC, and recognized by IAM Patent 1000 as a leading patent litigator.

Areas of FocusIntellectual PropertyTechnologyLitigation, Arbitration and InvestigationsCourt Trial Capabilities
Bar admissionsDistrict of ColumbiaVirginiaUnited States Patent and Trademark Office
CourtsUnited States District Court for the Eastern District of VirginiaUnited States District Court for the Eastern District of MichiganUnited States Court of Appeals for the Fourth CircuitUnited States Court of Appeals for the Federal CircuitUnited States Court of Federal Claims
Education

  • J.D., George Washington University, with honors

    Managing Editor, George Washington; Journal of International Law & Economics

  • B.S., Mechanical Engineering, Michigan State University, with honors

EXPERIENCE

  • Represented complainants in an ITC investigation in which the ITC issued a Limited Exclusion Order barring the importation of respondents’ infringing nickel manganese cobalt lithium oxide cathode materials following the agency’s first oral hearing in a Section 337 investigation in a decade.
  • Represented a respondent in an ITC investigation, obtaining a complete victory in a case involving seven patents and more than 100 claims in which the complainant sought to exclude all of the respondent’s smartphones and tablets.
  • Represented a respondent and several of its customers in an ITC investigation, obtaining a complete victory in a four-patent case in which the complainant sought to exclude all of the respondent’s flash memory products and numerous downstream products containing that technology.
  • Represented a third-party defendant on behalf of an independent agency of the US federal government in the US Court of Federal Claims, obtaining a summary judgment of noninfringement on all patents and claims. The US Court of Appeals for the Federal Circuit affirmed the lower court’s summary judgment.
  • Represented a plaintiff pharmaceutical manufacturer in the US District Court for the Eastern District of Virginia, obtaining summary judgment that rules promulgated by the US Patent and Trademark Office exceeded the agency’s statutory authority. The matter was recognized as US Patent Case of the Year 2009 by Managing Intellectual Property.
  • Represented a complainant in an ITC investigation, obtaining Limited Exclusion Orders and Cease and Desist Orders. The matter was subsequently settled before the hearing in the related enforcement proceeding.

AWARDS AND RECOGNITION

Chambers USA

  • Band 2, International Trade: Intellectual Property (Section 337), 2021–2026

The Legal 500 US

  • Recommended, Patents: Litigation (International Trade Commission), 2024–2026 
  • Recommended, Patents: Litigation (Full Coverage), 2024
  • Leading Lawyer, Antitrust: Cartel, 2023
  • Recommended, Trademarks: Litigation, 2018

Additional recognitions

  • Leading patent litigator, IAM Patent 1000, 2014–2026
 

Memberships and Affiliations

  • Member, International Trade Commission Trial Lawyers Association
  • Member, Federal Circuit Bar Association

My latest insights

News

DLA Piper expands market-leading patent litigation and ITC practices with addition of...

8 October 2026 .4 minute read

Connect

Phone

+1 202 799 4280
(Work, Washington, DC)
CallvCardLinkedInPrint