Katherine V. Mackey focuses her practice on complex litigation matters, including commercial litigation, internal investigations, and appeals. She has represented a variety of companies, including a major automotive manufacturer, a financial services company, and an electronics company.

Prior to joining the firm, Ms. Mackey served as a law clerk for the Honorable John M. Walker, Jr., of the US Court of Appeals for the Second Circuit and was an associate at a New York law firm. While in law school, Ms. Mackey was an intern at the US Attorney's Office for the District of Massachusetts in the Anti-Terrorism Unit.


  • “Reforming 'The Blob': Why California's Latest Approach to Amending CEQA Is a Bad Idea,“ 39 Colum. J. Envtl. L. 357 (2014).


  • Selected for inclusion in Best Lawyers: Ones to Watch for white-collar criminal defense (2022–2024) and appellate practice (2023–2024).

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  • Education

    • JD, Columbia Law School, 2014

      Executive Editor, Columbia Journal of Environmental Law

    • MA, University College London, 2011

    • BA, Harvard University, 2007

      cum laude

  • Admissions

    • Massachusetts

    • New York

    • US Court of Appeals for the Ninth Circuit

  • Clerkships

    • The Hon. John M. Walker Jr., US Court of Appeals for the Second Circuit, 2015 - 2016