William J. Barrow is a partner in Mayer Brown’s Intellectual Property Group. Bill leverages his electrical engineering background to litigate high-tech patent disputes in US district court and before the US International Trade Commission (ITC); challenge and defend patents in post-grant proceedings before the US Patent and Trademark Office (USPTO); and counsel clients on IP issues that arise during commercial transactions. Clients rely on Bill not just to manage their matters, but as a trusted advisor to advance and protect their business and technology interests.

  • Patent Litigation. Bill has litigated patent infringement cases from inception through trial, on the plaintiff and defendant side. His litigation experience spans over a dozen years and countless industries, with a particular emphasis on consumer electronics, telecommunications, software, and automobiles. In 2018, Bill played a critical role in obtaining a $43.3 million verdict from ZTE USA on behalf of Maxell, Ltd., conducting direct and cross examinations of key technical witnesses at trial. Bill has also secured numerous early favorable settlements for clients in defensive patent litigations.
  • Post-Grant USPTO Proceedings. Bill has extensive experience challenging and defending patents in inter partes review (IPR) before the US Patent Trial and Appeal Board (PTAB). Bill began his career prosecuting electrical and computer software patents, and is often sought out for his understanding of the interplay between litigation and USPTO procedure. His experience in this regard leads to the early identification of favorable case strategies and mechanisms for implementing those strategies in concert with his clients’ business goals.
  • Transactional Practice. Bill also leverages his technical and IP expertise to counsel clients on corporate IP matters. Bill has experience evaluating IP issues in commercial transactions, including conducting IP due diligence for mergers and acquisitions, divestitures, joint ventures, and strategic alliances.

Bill is frequently invited to speak and write on complex intellectual property issues, including litigation strategy, licensing, post-grant proceedings before the USPTO, and IP valuation, as well as emerging technologies, including artificial intelligence (AI), blockchain, cryptocurrency, NFTs, and the metaverse. Bill has also held leadership positions in a number of prominent legal/IP organizations. For example, Bill currently Chairs the American Intellectual Property Law Association’s (AIPLA) Patent Litigation Committee, and is a former Chair of the National Bar Association’s (NBA) IP Section. In 2018, Mayer Brown selected Bill as its sole Fellow for the Leadership Council on Legal Diversity’s (LCLD) Fellowship Program. Since then, Bill has served as a City Lead for LCLD’s Alumni and Success in 1L Mentoring Programs. Presently, Bill serves on LCLD’s Alumni Leadership Symposium Committee.

Bill serves on Mayer Brown’s Talent Development Team, as well as the Washington DC office’s Recruiting and Mentorship Committees. Bill is also the founder and a Co-Chair of Mayer Brown Black Lawyers (DC), an affinity group Bill established to foster and promote the recruiting and retention of African-American attorneys in the firm’s DC office.

In 2021, Bill was named a “DC Rising Star” by the National Law Journal for his influence in his practice area, demonstrated leadership qualities, and significant community impact. Since 2014, Bill has been recognized as a "Rising Star" in intellectual property by Super Lawyers Magazine.


  • Presently representing Maxell, Ltd. in a number of US district court patent litigation matters pertaining to smart phone technology. Key contributor on trial team (conducting direct and cross examinations of witnesses at trial) that secured $43.3 million verdict against ZTE USA in E.D. Tex.
  • Represented LG Electronics, Inc. in a variety of US district court matters pertaining to telecommunications and various other aspects of mobile phones and tablets. Role included managing day to day operations of cases; working closely with client to develop litigation and technical strategies, including with respect to reexamination and petitions for inter partes review (IPR); managing team of associates on technical, legal, damages, and discovery-related issues; arguing in court, e.g., at Markman hearings and regarding various discovery, legal, and pre-trial issues; and taking and defending fact and expert depositions.
  • Represented LG Display in a patent infringement suit (D. Del.) and related PTAB proceeding that eventually culminated in cancellation of asserted claims and dismissal of litigation with prejudice. Relevant experience included managing day to day operations of case; developing litigation and technical strategies; preparing and successfully arguing IPR petition before PTAB.
  • Represented General Motors against allegations of patent infringement regarding vehicle stereo systems in E.D. Tex. Role included managing technical module of case, and developing technical and licensing positions for same; arguing claim terms at Markman hearing; and taking and defending fact and expert depositions.
  • Represented Mitsubishi Electric before ITC against allegations of patent infringement regarding Smart TVs. Role included developing technical positions for patents; and taking and defending fact and expert depositions.
  • Represented Hyundai and Kia before ITC against allegations of patent infringement regarding in-dash GPS navigation systems. Role included managing technical module of case; managing team of associates on technical and discovery-related issues; and taking and defending fact and expert depositions.


American University Washington College of Law, JD
Senior Staff, Administrative Law Review

University of Pennsylvania, BS, Electrical Engineering


  • District of Columbia
  • Maryland


  • US District Court for the Eastern District of Michigan
  • US District Court for the Western District of Texas
  • US District Court for the Eastern District of Texas
  • US Court of Appeals for the Seventh Circuit
  • US Patent and Trademark Office


  • American Intellectual Property Law Association, Patent Litigation Committee, Chair (Present), Vice Chair (2020-2021), Diversity Subcommittee Co-Chair (2016-2019), Professional Programs Subcommittee Vice Chair (2018-2019); Professional Programs Committee, CLE Coordinator (2015-Present)
  • National Bar Association, Intellectual Property Section, At-Large (2018-Present), Chair (2017-2018), Vice Chair (2016-2017), CLE Coordinator (2015-2016); Commercial Law Section, CLE Committee Member (Present)
  • Leadership Council on Legal Diversity, Alumni Symposium Committee Member (Present), Alumni City Lead (2019-2020), Mentorship Program City Lead (2019-2020), Fellow (2018)
  • Co-Chair and Founder of Mayer Brown Black Lawyers (DC)
  • American Bar Association
  • Federal Circuit Bar Association
  • ITC Trial Lawyers Association
  • Rebuilding Together DC Alexandria, Board Member