O’Melveny Worldwide

Mattie Hutton specializes in product liability, mass torts, class actions, and other complex civil litigation. Mattie advises clients at all stages of litigation, from discovery through appeal, and has argued before the U.S. Supreme Court and U.S. Court of Appeals for the Fourth Circuit. She also serves as trial counsel and key strategist for companies facing complex and high-value claims. For example, Mattie defended a major pharmaceutical company in opioids-related litigation in several states, and represented a medical device company in a nine-week consumer fraud bench trial against the California Attorney General.

Recognized as one of the leading litigators of her generation, the National Law Journal named Mattie a 2023 "Rising Star" and Bloomberg Law recognized her in its 2023 edition of “They’ve Got Next: The 40 Under 40.”

Mattie also maintains a dynamic pro bono practice, and is a member of the Board of Directors of the Capital Area Immigrant Rights Coalition. Prior to joining O’Melveny, Mattie clerked for the Honorable Robert C. Chambers, US District Judge, Southern District of West Virginia.

  • Representing a major medical device company in motions practice, post-trial briefing, and on appeal of product-liability claims in multiple jurisdictions
  • Representing a top entertainment company in constitutional and commercial litigation
  • Representing a leading banking institution in retrial of fraud action
  • Representing consumer-product company in multi-state suite of putative class actions
  • Representing medical device and pharmaceutical companies in federal multi-district litigation, coordinated state proceedings, multi-plaintiff state proceedings, and state attorney general actions
  • Defending a government-sponsored enterprise in securities class actions and ERISA litigation
  • Defending a major liability insurer in appeal of multi-decade coverage litigation
  • Advising an industrial materials manufacturer on regulatory and litigation exposure

Pro Bono Matters

  • Litigating and arguing an immigration appeal in the Fourth Circuit and United States Supreme Court
  • Litigating and arguing a prisoner civil rights appeal in the Fourth Circuit, leading to a published decision revising district court procedures for supervising similar claims
  • Representing multiple disability rights organizations as amici in the Second Circuit
  • Representing advocacy organizations in constitutional challenges to state laws
  • Obtaining cancellation of removal for a detained permanent resident
  • Advising a not-for-profit health advocacy organization on health information privacy and regulatory compliance obligations
  • Conducting an internal investigation for a non-profit organization
  • Obtaining asylum for a detained adult applicant, and securing derivative asylum for her young child


  • Spanish


Bar Admissions

  • California
  • District of Columbia

Court Admissions

  • US District Court for the Northern, Central, and Southern Districts of California
  • United States Court of Appeals for the Second and Fourth Circuits


  • Georgetown University, J.D.: cum laude, Barristers’ Council; Administrative Editor, American Criminal Law Review; Street Law Clinic
  • Stanford University, M.A., Communication
  • Stanford University, B.A., Political Science

Honors & Awards

  • Recommended by The Legal 500 US for State Attorneys General (2024)

Professional Activities


  • Honorable Robert C.  Chambers, US District Court, Southern District of West Virginia 


  • Contributor, Appleseed Foundation, Practitioner Guide, “Protecting Assets and Child Custody in the Face of Deportation” (2017)
  • “Jurisdictional Tactics: Will the Courts Allow Plaintiffs to Circumvent CAFA’s Mass Action Provision and Keep Mass Torts in State Courts?” California Litigation Review (2013)