O’Melveny Worldwide

Jason Zarrow’s practice is devoted to creating and executing legal strategy for bet-the-company litigation. From the beginning of the case—and often before litigation is ever filed—Jason serves as a trusted advisor for clients to develop comprehensive strategies to eliminate or substantially limit liability.

In the pre-suit phase, Jason advises clients on compliance options and litigation risks, with an eye toward building legal and factual arguments if litigation ensues. Once litigation begins, Jason coordinates legal and appellate strategy, starting with dispositive motions before the trial court. As the case progresses, Jason oversees the development of key points in the factual record, working with trial teams to ensure that his client’s legal arguments have the best factual framing at summary judgment, class certification, trial, and on appeal. And should the case proceed to trial, Jason has extensive experience as on-the-ground appellate counsel, presenting forceful arguments for judgment, crafting jury instructions, and ensuring all appellate points are preserved.

Jason’s expertise spans multiple industries, including transportation, pharmaceutical, consumer products, healthcare, insurance, and financial services. He is particularly well versed in the law of federal preemption, having filed numerous briefs in trial and appellate courts on (among other things) Airline Deregulation Act preemption and drug/device preemption. Jason also has a mastery of complex procedure, including substantial experience litigating class actions and crafting legal strategies designed to defeat or limit class certification. 

Although much of Jason’s practice is dedicated to bringing an appellate lawyer’s eye to trial work, he is also an experienced appellate advocate—both defending favorable trial judgments and overturning unfavorable ones. He has authored numerous merits, amicus, and cert-stage briefs in the US Supreme Court and even more in state and federal courts of appeal. He handles not only post-judgment appeals, but interlocutory appeals as well. Indeed, as part of a comprehensive legal strategy, Jason often advises clients on options and strategies for interlocutory review, including of class certification decisions under Rule 23(f). Jason has been recognized for his appellate work by Legal 500.

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  • Co-authored numerous appellate and trial court briefs on the scope of Airline Deregulation Act preemption
  • Co-authored numerous appellate and trial court briefs on whether paid military leave is required under USERRA
  • Co-authored numerous briefs on the scope of Railway Labor Act preemption
  • Co-authored brief on the intersection of abstention doctrine and Railway Labor Act preemption
  • Served as national appellate counsel for medical device manufacturer in nationwide products liability litigation
  • Coordinated legal strategy in multi-billion dollar suit by state attorney general challenging pharmaceutical marketing
  • Coordinated legal strategy in billion dollar suit by state attorney general challenging medical device marketing
  • Co-authored successful appellate briefs reversing multi-million dollar jury award based on erroneous exclusion of regulatory evidence in product liability trial involving prescription-only medical device
  • Served as on-the-ground appellate counsel at several products liability trials
  • Co-authored successful motion to dismiss briefs in case challenging pharmaceutical pricing
  • Co-authored merits brief in Dubin v. United States, regarding the scope of the federal aggravated identity theft statute. Argued en banc in the Fifth Circuit.
  • Co-authored merits brief in Ciminelli v. United States, regarding the scope of the federal criminal fraud statutes
  • Co-authored successful merits brief in Jam v. International Finance Corp., 139 S.Ct. 759 (2019), which clarified the scope of international organizational immunity under the International Organizations Immunities Act
  • Co-authored successful merits brief in Ayestas v. Davis, 138 S. Ct. 1080 (2018), which clarified the standard for receiving funding for investigative services in capital cases under 18 U.S.C. § 3599(f)
  • Co-authored successful merits brief in China Agritech Inc. v. Resh, 138 S. Ct. 1800 (2018), which held that the tolling rule of American Pipe & Construction Co. v. Utah, 414 U.S. 538 (1974), does not apply to successive class actions
  • Argued and prevailed in the Fourth Circuit in Harwood v. American Airlines, Inc., concerning mitigation of damages and attorney’s fees under the federal military reemployment statue (USERRA)
  • Argued and prevailed in the Fifth Circuit in Williams v. Reeves, which held that state sovereign immunity did not bar school rights suit under statute readmitting Mississippi to representation in Congress after the Civil War. Successfully defeated en banc review in the Fifth Circuit and stay application in the Supreme Court.
  • Argued and prevailed in the Fourth Circuit in Sotnikau v. Lynch, which held that involuntary manslaughter is not categorically a crime involving moral turpitude
  • Co-authored successful briefs in appeal challenging classification of real estate agents as independent contractors under California law
  • Co-authored successful briefs in wage-and-hour class action, resulting in reversal of class certification
  • Co-authored successful briefs in appeal affirming dismissal of plaintiffs’ claims challenging the common practice of credit “freezes” for lack of standing


Bar Admissions

  • California

Court Admissions

  • US Supreme Court
  • US Court of Appeals, Second, Third, Fourth, Fifth, Sixth, Seventh, Ninth, and District of Columbia Circuits
  • US District Court, Central District of California, Western District of Wisconsin, and District of Colorado


  • Harvard University, J.D.: magna cum laude
  • Vanderbilt University, B.A., Economics and History: summa cum laude

Honors & Awards

  • Recognized by The Legal 500 US for Appellate (2020)

Professional Activities


  • Honorable Julia Smith Gibbons, United States Court of Appeals, Sixth Circuit


  • “Retroactivity, the Due Process Clause, and the Federal Question in Montgomery v. Louisiana,” 68 Stan. L. Rev. Online 42 (2015)
  • “The Retroactivity of Substantive Rules to Cases on Collateral Review and the AEDPA, with a Special Focus on Miller v. Alabama,” 48 Ind. L. Rev. 932 (2014)