O’Melveny Worldwide

Jon Hacker chairs O’Melveny’s Supreme Court and Appellate Litigation Practice and resides in the firm’s Washington, DC office.

Top-ranked by Chambers USA since 2012, Jon is regarded by peers as “a phenomenal writer” and “a forceful advocate.” He has authored briefs in dozens of US Supreme Court cases at both the merits and certiorari stages. He has argued six cases in the US Supreme Court and appeals in every federal circuit. He has also briefed and argued appeals in numerous state courts, including New York, California, Ohio, Pennsylvania, Florida, Massachusetts, New Jersey, Maine, Montana, Nebraska, and the District of Columbia. Clients praise him as “such a down-to-earth person but an unparalleled oral advocate.”

Jon’s appellate work has resulted in reversals of trial-court judgments (including jury verdicts) worth tens of millions and even billions of dollars. He has also briefed and argued many trial-level matters, has conducted discovery and depositions in complex litigation matters, and has handled several trials. Jon earns repeated praise for his “outstanding written product,” with peers in the field impressed by his “bullet-proof performances in difficult cases.”

Jon’s areas of expertise include federal constitutional law, insurance, ERISA, criminal law and procedure, and federal jurisdiction and procedure. He is highly regarded by leading industry publications, including the American Lawyer as “Litigator of the Week”, Wall Street Journal as a “Rising Appellate Star”, National Law Journal as “Appellate Lawyer of the Week”, Chambers USA and Legal 500 as a leading nationwide practitioner, Benchmark Litigation as a “Local Litigation Star”, and Best Lawyers in America as a recognized lawyer since 2010.

Jon was a Lecturer in appellate advocacy for five years at the Harvard Law School, where he co-founded and co-directed the HLS Supreme Court and Appellate Advocacy Clinic. He is Co-Chair of the Supreme Court Amicus Committee of the National Association of Criminal Defense Lawyers.

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Bar Admissions

  • District of Columbia
  • Maryland

Court Admissions

  • US Supreme Court
  • All federal circuit courts of appeal
  • US District Court, District of Columbia 


  • University of Michigan, J.D., 1995:  magna cum laude; Order of the Coif; Henry M. Campbell Memorial Scholarship (Law School’s highest award for graduates); Managing Editor, 1994-95, Associate Editor, 1993-94, Michigan Law Review; Winner, Campbell Moot Court Competition, 1994
  • Harvard College, A.B., 1990 (Social Studies): cum laude

Honors & Awards

  • Recognized by Chambers USA in the category of Appellate Law (2021-2024)
  • Recognized by Best Lawyers® for Appellate Practice in Washington, DC (2022-2024); Jon has been listed in Best Lawyers® since 2010
  • Recognized by The Legal 500 US as a Leading Lawyer for Appellate (2020, 2022, 2024); Listed in The Legal 500 US since 2017
  • Repeatedly selected as a leading US appellate lawyer by Chambers
  • “Superstar Of Insurance Law,” Insurance Business Magazine (2021)
  • “Local Litigation Star,” Benchmark Litigation (2018-2020, 2023-2024)
  • “Litigator of the Week,” The American Lawyer (August 2015)
  • “Rising Appellate Star,”  The Wall Street Journal (January 2011)
  • “Appellate Lawyer of the Week,” National Law Journal (2011)

Professional Activities


  • Honorable Bruce M. Selya, US Court of Appeals, First Circuit


  • Co-Chair, National Association of Criminal Defense Lawyers, Supreme Court Amicus Committee

Co-Founder and Co-Director

  • HLS Supreme Court and Appellate Advocacy Clinic, Harvard Law School