Skip to main content

Doug Winthrop, co-chair of the firm’s Intellectual Property practice group and a former United States Supreme Court law clerk, focuses his litigation practice on intellectual property and unfair competition, business torts, claims of breach of fiduciary duty, contract disputes, and class action defense at both the trial court and appellate levels.

Doug has represented numerous technology, manufacturing, consumer products and financial services companies in matters raising claims of trade secret misappropriation, breach of fiduciary duty, misrepresentation, breach of the implied covenant of good faith and fair dealing, and breach of contract, as well as in consumer class actions and copyright and trademark suits. He recently defended an international manufacturer against parallel federal and state litigation asserting trade secret misappropriation and trademark infringement, and previously defended trade secret misappropriation claims against one of the world's largest semiconductor manufacturers, resulting in a dismissal of claims and an award of fees against the plaintiff. He also has extensive experience in complex commercial litigation. Since 2007, he has represented a U.S. mortgage insurance company in multimillion-dollar rescission litigation as well as the successful trial defense of claims challenging mortgage insurance benefit curtailments. Doug successfully represented Quicken Loans, at both the trial court and on appeal, in the defense of a class action suit claiming violation of California law relating to interest payments on property insurance proceeds.

Doug was honored with the Artistic Freedom Award by the ACLU of Southern California for his and his colleagues' successful representation of artist Thomas Forsythe against claims of trademark and copyright infringement brought by Mattel Inc. (Mattel Inc. v. Walking Mountain Prods., 353 F.3d 792 (9th Cir. 2003)).

Doug served as law clerk to Associate Justice John Paul Stevens of the United States Supreme Court, 1992–1993, and to Judge Patricia M. Wald of the United States Court of Appeals for the District of Columbia Circuit, 1991-1992.

Doug graduated magna cum laude from the University of Minnesota Law School, where he was an Editor of the Minnesota Law Review and was awarded the Order of the Coif.


  • Leading Chinese consumer electronics component manufacturer in defense of parallel federal and state court trademark and trade secret actions.
  • American subsidiary of Japanese semiconductor company in defense of patent infringement action.
  • PMI Mortgage Insurance Co., in Rehabilitation, and its court-appointed receiver in prosecution of trade secret misappropriation, breach of fiduciary duty, and conversion claims against former employees and competitor.
  • Aircraft manufacturer in successful defense in federal district court and on appeal of right of publicity claims by former test pilot Chuck Yeager.
  • Leading on-line retailer in prosecution of multiple trademark, copyright, and unfair competition claims against competitors.
  • American subsidiary of Japanese semiconductor company in defense of patent infringement action.
  • Employee of Inc. in defense of trade secret and breach of contract claims brought by former employer.
  • Leading on-line retailerin defense of Lanham Act false advertising claims.
  • Third-largest wine producer in the world in defense of trademark and unfair competition claims brought by competitor.
  • United States Olympic Committee in numerous trademark and unfair competition actions relating to, inter alia, ambush marketing, offshore gambling, the importation of infringing merchandise and claims of fair use.
  • Artist against claims by Mattel Inc. of trademark and copyright infringement. Mattel Inc. v. Walking Mountain Prods., 353 F.3d 792 (9th Cir. 2003).
  • Major U.S. apparel retailer against claims of copyright, trademark, and trade dress infringement related to advertising and in-store design.
  • Food retailer in defense of claims of, and in prosecution of related counterclaims for, trademark infringement.
  • Time Inc. in prosecution of trademark infringement and dilution claims involving one of Time's most well-known trademarks.
  • American Express Travel Related Services Inc. in defense of patent infringement litigation involving automated payment systems.


Best Lawyers
Commercial Litigation (SF) (2024)
Northern California Super Lawyers
"Legal Lion of the Week" (March 2020)



  • J.D., University of Minnesota Law School, 1991, magna cum laude, Order of the Coif
  • A.B., Harvard University, 1986, magna cum laude


  • California
  • District of Columbia


  • Supreme Court of the United States, The Honorable John Paul Stevens
  • United States Court of Appeals, District of Columbia Circuit, The Honorable Patricia M. Wald


  • Member, State Bar of California
  • Member, Bar Association of the District of Columbia
  • Member, Bar Association of San Francisco
  • Member, American Bar Association
  • Secretary, The John Paul Stevens Foundation
  • Member, Board of Directors, Jewish Family & Children's Services of San Francisco, The Peninsula, Marin and Sonoma Counties
  • Member, Advisory Council, Tahirih Justice Center