People

Andrew A. Lyonsberg

Associé

Washington, DC

Andrew Lyonsberg is a member of the Firm’s Supreme Court & Appellate Litigation and Government & Regulatory Litigation practices. An experienced appellate litigator, he has briefed more than one hundred appellate matters and dispositive trial-court motions and has argued before the US Courts of Appeals for the Fifth, Sixth, Seventh, and Eighth Circuits, and the Delaware Supreme Court. Andrew has extensive experience with agency litigation under the Administrative Procedure Act, developing and executing legal strategies to successfully challenge regulations and other federal, state, and local government actions across a wide range of industries and areas of substantive law.

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Results
  • Obtained vacatur of an SEC proxy-advice regulation in the Fifth Circuit on behalf of a leading national trade association
  • Argued and won a Medicare-related False Claims Act appeal in the Seventh Circuit on behalf of a premier university health system
  • Won a mandamus action against FDA in the US District Court for the District of Columbia, requiring the agency to adhere to statutory deadlines for drug application review

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Recognitions
  • Best Lawyers: Ones to Watch in America, Appellate Practice, 2023-2026
  • Legal 500 US, Rising Star in Appellate & Supreme Court Litigation, 2022; Appellate & Supreme Court Litigation, 2021-2025
  • District of Columbia Courts, Capital Pro Bono Honor Roll, 2023
Capabilities and Industries
Marchés Régionaux
Community
  • Yale Law School, visiting clinical lecturer in law, 2023 to present
Credentials
Education
  • Yale Law School, JD
  • Williams College, BA, magna cum laude
Admissions
  • District of Columbia
  • Maryland
Courts / Agencies
  • Supreme Court of the United States
  • US Court of Appeals for the Second Circuit
  • US Court of Appeals for the Fourth Circuit
  • US Court of Appeals for the Fifth Circuit
  • US Court of Appeals for the Sixth Circuit
  • US Court of Appeals for the Seventh Circuit
  • US Court of Appeals for the Eighth Circuit
  • US Court of Appeals for the Ninth Circuit
  • US Court of Appeals for the Federal Circuit
  • US Court of Appeals for the District of Columbia Circuit
  • US District Court for the District of Columbia
  • US District Court for the District of Maryland