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Best Litigation Attorneys in San Jose
Expertise - Best Employment Lawyers in Santa Clara 2021
Expertise - Best Employment Lawyers in Santa Clara 2022
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Patrick E. O’Shaughnessy

Litigation Counsel
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Phone: (408) 436-0789

1754 Technology Dr #122
San Jose, California 95110

Patrick serves as of-counsel of our firm. Whether the legal challenges with which you need help require counseling, in-court representation, or another means of dispute resolution, Patrick has in depth experiences and uncommon perspective to share to help inform your business decisions. His extensive substantive litigation experience, at both federal and state levels, in jurisdictions throughout the country, provides him with unique and broad-based insights that he uses to help clients find practical solutions to real-world problems.

Patrick’s business litigation and counseling experience includes antitrust, breach of fiduciary duty and breach of contract disputes, most often in connection with business ownership disputes. He also has significant experience in IP/antitrust analysis and trade secret and copyright disputes.

Despite his zeal for the courtroom, Patrick’s approach is customer-service focused. He emphasizes practical and client-centered business solutions. Many of his most gratifying accomplishments as a lawyer involve engagements where his clients do not appear in court.

Previously, Patrick served in private practice in San Francisco, California, Columbus and Dayton, Ohio, and Washington, DC, and in government enforcement in Washington, DC as a Trial Attorney at the U.S. Department of Justice, Antitrust Division, which he joined through the Attorney General’s Honors Program, and in Columbus, Ohio as a Senior Assistant Attorney General at the Ohio Attorney General’s Office, Antitrust Section. While at the U.S. Department of Justice, Patrick was selected to serve as a Special Assistant United States Attorney for the U.S. Attorney’s Office in the Eastern District of Virginia and also as a Special Assistant for the U.S. Department of Justice, Antitrust Division’s Directors of Civil and Criminal Enforcement.

Patrick grew up in Columbus, Ohio and proudly considers himself a Buckeye. He enjoys spending time with his family, following his longtime favorite Los Angeles Lakers, going to baseball games, and playing golf in the Bay Area as often as possible.


J.D., UCLA School of Law, 2001
Editor-in-Chief, Journal of International Law and Foreign Affairs
Best Moot Court Team, Distinguished Advocate, and Outstanding Brief Writer Awards
National Moot Court Team

B.A., Cornell University, 1998
cum laude

Jurisdictions Admitted to Practice Ohio, 2009
District of Columbia, 2006
California, 2001
Past Employment Positions
  • U.S. Department of Justice, Antitrust Division
  • Ohio Attorney General’s Office
  • Bartko Zankel Bunzel & Miller, PC
  • Sebaly Shillito + Dyer, LPA
  • Robins, Kaplan, Miller & Ciresi, LLP
  • Crowell & Moring, LLP
  • English
Recent Writing
Client Reviews
Mr. Cai Is a Diligent Attorney. My sister and I were defendants in a civil litigation case. We hired James Cai and his law firm, SAC Attorneys LLP. Mr. Cai is a diligent attorney and responded to our questions in a timely fashion. He and his staff were very helpful in keeping us informed of the proceedings of the case and in explaining each step. Mr. Cai is also very conscientious of fees and costs, and avoided unnecessary charges. The results of the Summary Adjudication sided with us. The Court Trial resulted in the “Final Statement of Decision” and “Judgment after Court Trial” overwhelmingly siding with us. Cynthia F.
I Am Truly Impressed. After spending a significant amount of time, money and efforts with my previous counsel at a larger law firm without getting meaningful results, I transferred my employment matter to SAC Attorneys LLP. The attorneys there were able to understand the complex situations of my case and put together an aggressive litigation strategy. We were able to file a compelling complaint within a week and forced the opposing party, which was represented by one of the largest law firms in California, to make a substantial settlement offer shortly thereafter. I am truly impressed by the no nonsense and results oriented approach by SAC Attorneys LLP attorneys. A job well done! X. Gao
They Took Time to Understand Our Technology. I am the founder of a bioinformatics start-up in the Silicon Valley and chose SAC Attorneys LLP as our corporate counsels. Their attorneys have great experience with high tech start-ups and were able to offer a highly competitive service plan while not sacrificing a bit of their quality of services. They took time to understand our technology and provided value added services by introducing investors and job candidates to us. We regard our attorneys at SAC Attorneys LLP not only as our legal advisors but also our venture partners. Dr. Pete S.