Add a bookmark to get started

David Horniak

David Horniak


David Horniak litigates complex, high-stakes civil and criminal cases at the trial and appellate levels. His clients range from Fortune 500 corporations to individuals and startups, and he has successfully represented them in a broad range of disputes involving advertising, patents, tax, securities, legal malpractice, and commercial and government contracts. He currently focuses his practice on three areas:  (1) defense of food, pet, consumer goods, and e-commerce companies in class actions and other litigation; (2) representation of technology and pharmaceutical companies in intellectual property and other litigation; and (3) defense of civil and criminal  investigations and litigation brought by federal and state government authorities. 

David has successfully argued numerous motions and appeals, taken and defended countless depositions, had an active role in multiple trials, and authored many dispositive motions and appellate briefs. As reported by The Legal 500, clients describe him as "easily accessible" and "respectful," someone who "quickly responds to client inquiries with direct and helpful communication." He "always takes the time needed to ensure in-house counsel are up-to-speed and understanding of the process and issues." He was named to the Washington, DC "Rising Stars" list in the 2014–2019 editions of Super Lawyers.

Born in California and raised in Minnesota, David graduated with honors from Dartmouth College, where he studied computer science, rowed varsity crew, and was selected Academic All Ivy in the 2002 and 2003 seasons. After college, he managed operations for a distribution company in the Chicago area, where he assisted in the design and expansion of that company’s facility. David received his J.D. from the University of Michigan Law School, where he graduated magna cum laude, was a member of the Order of the Coif, and served as an editor of the Michigan Law Review. Following law school, David clerked in Seattle for Judge Ronald M. Gould of the U.S. Court of Appeals for the Ninth Circuit before entering private practice.  He lives in the District of Columbia with his wife and three sons.

Bar admissionsCaliforniaDistrict of Columbia
CourtsSupreme Court of the United StatesUnited States Court of Appeals for the First CircuitUnited States Court of Appeals for the Second CircuitUnited States Court of Appeals for the Ninth CircuitUnited States Court of Appeals for the District of Columbia CircuitUnited States District Court for the District of ColumbiaUnited States District Court for the Northern District of CaliforniaUnited States District Court for the Central District of CaliforniaUnited States District Court for the Southern District of CaliforniaUnited States Tax Court


David’s experience includes:

Food, Pet, Consumer Goods, and E-Commerce Defense

  • Defending a pet-food manufacturer in multiple consumer class action lawsuits in the Southern District of Florida. The district court dismissed the complaints with prejudice.
  • Defending a packaged-food manufacturer in a consumer class action lawsuit in the District of Massachusetts. The district court dismissed the complaint with prejudice, and the First Circuit affirmed the decision on appeal.
  • Defending a fast-food franchisor in California consumer class-action lawsuits alleging false advertising.  The district court compelled individual arbitration as to two plaintiffs and dismissed a third plaintiff’s complaint with prejudice.
  • Advising e-commerce companies on revisions to their websites to reduce litigation risk.

Technology and Pharmaceutical Litigation

  • Prosecuting a multi-week trial in the District of New Jersey for a branded pharmaceutical company’s patent-infringement claims.
  • Prosecuting a branded pharmaceutical company’s patent infringement claims in federal multi-district litigation against more than a dozen generics.
  • Defending inter partes review petitions challenging patents covering a novel cancer therapy.
  • Defending product defect claims against a public technology company.
  • Prosecuting, through trial, a public technology company’s claims for breach of a government contract.

Government Investigations and Litigation

  • Defending the chairman of an investment firm in a DOJ criminal tax investigation.
  • Representing the chief executive of a global auto industry manufacturer in a DOJ criminal fraud investigation.
  • Representing a trader at a major bank in an SEC securities fraud investigation.
  • Prosecuting, on behalf of multiple clients, petitions in US Tax Court challenging tax deficiencies asserted by the IRS.
  • Representing testifying witnesses in multiple federal criminal prosecutions.
  • Defending multiple clients in investigations by state attorneys general.
  • Prosecuting an individual’s successful appeal from a conviction for second-degree assault.
  • Representing an individual in the US Supreme Court in an appeal addressing the constitutionality of DNA swabbing at the time of the arrest.

Other Experience

  • Defending multiple global law firms against allegations of legal malpractice and related claims.
  • Prosecuting a financial services firm’s claims seeking damages for breach of a data provision contract through a commercial arbitration hearing. 
  • J.D., University of Michigan Law School
    Order of the Coif
    Contributing Editor, Michigan Law Review
    magna cum laude
  • A.B., Computer Science, Dartmouth College
    cum laude


  • Super Lawyers Rising Star, 2014-2019


  • Co-authored, ""SPAC" Clients Pose Unique Risks for Law Firms: Lessons Learned from Defending Lawyers in Malpractice Cases," CNA, November 2021


  • Speaker, "Food and Beverage Litigation – Recent Trends, Issues and Challenges Explored," October 2020
  • Speaker, "Inequitable Conduct After Therasense," 2018

Media Mentions

Clerk Experience

  • Clerkship: Judge Ronald M. Gould, US Court of Appeals for the Ninth Circuit, Seattle, WA

Memberships And Affiliations

  • D.C. Committee on Unauthorized Practice of Law (appointed by D.C. Court of Appeals)
  • American Bar Association
  • District of Columbia Bar Association
  • California Bar Association