About Katherine Mayer
Katherine Mayer Mangan began her path to law at Pomona College, where she earned a B.A. in 1996. She continued her studies at Georgetown University and received her J.D. in 2001. Those years anchored a trajectory that moved from policy work in Washington to courtroom practice on the West Coast.
Her first notable role after law school was as a legislative aide in the Office of Senator Jeff Bingaman in 2000. That early exposure to federal lawmaking shaped an interest in the institutional side of law. She served as a law clerk to a judge on the United States Court of Appeals for the Ninth Circuit in 2004, a position that provided intensive experience with appellate briefing and opinion drafting.
In 2005 she joined the U.S. Department of Justice through the Trial Attorneys General's Honors Program. The stint at Justice added federal trial and appellate litigation to her skill set. She moved into private practice as a litigation associate at Latham & Watkins LLP in 2006, where she worked on complex civil matters and appellate filings.
Mangan founded the Appellate Litigation Clinic in 2009 and has served as its director since then. The clinic gave junior lawyers and law students a supervised setting to handle appeals and to learn the mechanics of appellate argument. Her colleagues point to the clinic as a place where practical courtroom preparation meets close editorial review of briefs.
She has been the chair of the Appellate Court Committee of the San Diego County Bar Association since 2011. In that role she has organized panels, hosted oral argument workshops, and helped coordinate court observations for members. The committee work complements her litigation practice by keeping her connected to changes in appellate procedure and to the local bench and bar.
Mangan is admitted to practice in California and to the United States Court of Appeals for the Ninth Circuit. Her experience spans both trial and appellate phases of litigation, and she regularly prepares briefs, motions, and appellate records. Her background includes federal government service, a federal clerkship, and private firm litigation experience, which together inform how she approaches appellate strategy and client counseling.
She practices at Mayer Mangan, PLC, where she continues to handle appeals and related litigation matters. Her current practice focuses on appellate litigation and counseling clients through complex post-trial and appellate procedures.
