​Thomas G. Hungar is a partner in the Washington, D.C., office of Gibson, Dunn & Crutcher LLP and Co-Chair of the firm’s Appellate and Constitutional Law Practice Group.  His practice focuses on appellate litigation, and he assists clients with complex trial court litigation matters as well.  He has presented oral argument before the Supreme Court of the United States in 26 cases, including some of the most important patent, antitrust, securities, and environmental law decisions issued by the Court in recent years, and he has also appeared before numerous lower federal and state appellate courts.  He is nationally ranked as an appellate attorney by Chambers USA: America’s Leading Business Lawyers and is listed as a Litigation Star for Washington, DC, and the Federal Circuit by Benchmark Litigation.  Mr. Hungar is also recognized as a Super Lawyer by Washington, D.C. Super Lawyers and is listed in Best Lawyers® as an appellate litigator.

Mr. Hungar previously served as a Deputy Solicitor General of the United States.  In that position, he supervised business-related appellate litigation for the federal government, with particular emphasis on patent, antitrust, securities, and environmental appellate cases, and he also oversaw appellate litigation in banking, bankruptcy, tax, government contracts, communications, copyright, labor, trademark, and international trade matters.  In private practice, Mr. Hungar’s appellate experience has encompassed those areas as well as constitutional law, class actions, employment law, product liability, administrative procedure, insurance coverage and bad faith, and general commercial litigation.  He has handled scores of business-related appeals in the Supreme Court and lower appellate courts, and has briefed and argued many high-profile matters.  According to CBS News chief legal correspondent Jan Crawford, Mr. Hungar has “dazzle[d] the justices with his arguments” before the Court.  Representative cases in which he has presented oral argument include:

  • Microsoft Corp. v. i4i Ltd. Partnership  (standard of proof for challenges to patent validity).
  • Stoneridge Investment Partners, LLC v. Scientific-Atlanta, Inc.  (rejecting “scheme liability” as basis for imposing liability on secondary actors in securities fraud actions under SEC Rule 10b-5 and Section 10(b) of the Securities Exchange Act of 1934).
  • Leegin Creative Leather Prods., Inc. v. PSKS, Inc. (overruling Dr. Miles rule of per se invalidity for vertical minimum resale price maintenance agreements under Section 1 of the Sherman Act).
  • KSR Int’l Co. v. Teleflex Inc. (clarifying standard for determining when an invention claimed in a patent is “obvious,” and therefore ineligible for patent protection, under Section 103(a) of the Patent Act).
  • Environmental Defense v. Duke Energy Corp. (Clean Air Act New Source Review case clarifying test for determining whether a “modification” to a pollutant-emitting source has occurred so as to require a permit under the Prevention of Significant Deterioration program).
  • Illinois Tool Works, Inc. v. Independent Ink, Inc. (overturning longstanding presumption of market power that arose in tying cases under Section 1 of the Sherman Act when the defendant held a patent on the tying product).
  • Quanta Computer, Inc. v. LG Electronics, Inc. (patent infringement action involving application of patent-exhaustion doctrine to method claims and to sales of components of patented systems).
  • Dura Pharmaceuticals, Inc. v. Broudo (requiring securities fraud plaintiffs invoking the fraud-on-the-market theory to plead and prove loss causation by identifying a causal connection between the alleged fraud and the security’s subsequent decline in price).
  • National Cable & Telecom. Ass’n v. Brand X Internet Servs. (upholding FCC’s determination that cable modem broadband Internet access service is solely an unregulated “information service” under the federal Communications Act and does not include a regulated “telecommunications service” component).

Mr. Hungar has been elected a Fellow of the American Academy of Appellate Lawyers and is a Master in both the Edward Coke Appellate American Inn of Court and the Giles S. Rich American Inn of Court.  He serves as a member of the Amicus Committee of the Federal Circuit Bar Association and is a frequent lecturer in his areas of expertise, appearing before such organizations as the American Academy of Appellate Lawyers, the Federal Circuit Bar Association, and the American Bar Association’s Business Law Section.  While at the Department of Justice, he served as Appellate Counsel to the Intellectual Property Task Force Executive Staff, and he was awarded the John Marshall Award for Outstanding Legal Achievement, the Department's highest award presented to attorneys for contributions and excellence in legal performance.

Mr. Hungar served as an Assistant to the Solicitor General of the United States from 1992-1994.  In that position he presented oral argument before the Court in six cases and handled numerous other appellate matters for the government.  He also served as a law clerk to Justice Anthony M. Kennedy of the Supreme Court and to Circuit Judge Alex Kozinski of the United States Court of Appeals for the Ninth Circuit.  He received his law degree from Yale Law School in 1987, where he was a Senior Editor of the Yale Law & Policy Review.  He received his bachelor of science degree magna cum laude in mathematics/computer science and economics from Willamette University in 1984.


  • Yale University - 1987 - Juris Doctor
  • Willamette University - 1984 - Bachelor of Science


  • California Bar
  • District of Columbia Bar