Diane Elizabeth Ghrist is an associate in the Washington, D.C. office of Latham & Watkins and a member of the Intellectual Property Litigation Practice.

Ms. Ghrist primarily advises on patent and trade secrets litigation. Her experience includes matters covering a range of technologies, such as automotive technologies, robotics, telecommunications, medical devices, and security software. Ms. Ghrist has represented OEM clients in the automotive industry, start-up companies in the medical device industry, and leading software developers. Ms. Ghrist has also participated in numerous post-grant proceedings before the US Patent and Trademark Office (USPTO). In addition, Ms. Ghrist has extensive experience advising on patent litigation actions against the US Government under 28 U.S.C. § 1498 and suits concerning waivers of sovereign immunity.

Prior to joining Latham, Ms. Ghrist clerked for Judge Jimmie V. Reyna of the US Court of Appeals for the Federal Circuit and for Judge Mary Ellen Coster Williams of the US Court of Federal Claims. During law school, Ms. Ghrist served as an editor for the American University Business Law Review. Ms. Ghrist earned her bachelor’s degree in mathematics and English language and literature from Bryn Mawr College.

Ms. Ghrist's experience includes:

  • CardioNet, LLC v. InfoBionic, Inc. Represented InfoBionic, a venture-backed manufacturer of wireless remote arrhythmia detection and monitoring system, after taking over as defense counsel in two cases with 7 asserted patents and trade secret misappropriation claims brought by CardioNet
  • Jaguar Land Rover Ltd. v. Bentley Motors Ltd.; Certain Vehicle Control Systems, Vehicles Containing the Same, and Components Thereof. Represented Jaguar Land Rover Limited, a British luxury automaker, in a patent litigation filed in the US District Court for the Eastern District of Virginia and before the US International Trade Commission and Patent Trial and Appeal Board
  • Pacific Coast Bldg. Prods., Inc. v. CertainTeed Gypsum, Inc. (N.D. Cal): Represented CertainTeed in multi-patent case relating to gypsum and viscoelastic glue products. Latham successfully invalidated the patents at summary judgment and successfully defended CertainTeed on appeal before the U.S. Court of Appeals for the Federal Circuit 
  • ZapFraud, Inc. v. Mimecast North America, Inc. Represented Mimecast, a network security company, in the US District Court for the District of Delaware, in patent litigation regarding automated detection of phishing attempts. Latham successfully obtained dismissal with prejudice of all claims under 35 U.S.C. § 101
  • Duolingo, Inc. v. Modern Font Applications; CoStar Realty Information, Inc. v. MFA. Represented Duolingo and Co-Star in actions for non-infringement related to patents on displaying non-standard fonts.  Latham successfully defended Duolingo before the the Federal Circuit after MFA sough appellate review and petitioned for mandamus relief.  Represented Duolingo and CoStar before the Patent Trial and Appeal Board
  • LET Investors Group, LLC v. Latchable, Inc. Represented Latchable, Inc., (Latch) a manufacturer of smart access systems, along with its CEO, Luke Schoenfelder and CTO, Brian Jones in the Virginia Circuit Court, regarding allegations by LETIG that Latch misappropriated trade secrets from a former company
  • Slice, Inc. v. Acme United Corporation. Represented Acme United Corporation and Office Depot in a lawsuit brought by Slice, Inc. in the US District Court for the District of New Jersey claiming infringement of a design patent and a utility patent related to ceramic blade cutting products. 

Bar Qualification

  • California
  • District of Columbia


  • JD, American University Washington College of Law, 2014
    cum laude
  • AB in Mathematics & English Language and Literature, Bryn Mawr College, 2007
    cum laude