Sean Patrick O’Neill is a trial lawyer specializing in litigating a wide variety of complex catastrophic personal injury, wrongful death, birth injury, elder abuse, medical malpractice and other professional liability cases on behalf of plaintiffs throughout California.


Immediately prior to joining McMahan Law PC, Mr. O’Neill gained valuable trial experience working at Reback, McAndrews, Kjar, Warford & Stockalper LLP where he defended medical professionals, hospitals, lawyers, and accountants in professional liability matters.  Sean also served as corporate counsel at United States Steel Corporation.  Reporting directly to the General Counsel, Sean assisted with the Company’s international trade enforcement litigation, the Company’s engagement on public policy issues, served as a support attorney during the Company’s collective bargaining negotiations, and advised the business units on a number of other high priority corporate matters.


While in law school, Sean clerked in the United States Senate, Judiciary Committee and for a number of litigation firms in Los Angeles. Mr. O’Neill was also selected to serve as a special editor to the Harvard Journal of Law & Public Policy.


Sean is a graduate of the University of Arizona and Pepperdine University School of Law.

Sean Patrick O'Neill, Esq.

Los Angeles Personal Injury Attorney

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Office Location


11755 Wilshire Boulevard

Suite 2370

Los Angeles, CA 90025

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