Robert C. O'Brien

Of Counsel
  • Awards & Recognition
  • In the news

Ambassador O'Brien, a co-founder of the firm, was the 28th National Security Advisor. He is an accomplished litigator, a skilled neutral, and an experienced diplomat. Recognized as one of the "Top 100 Lawyers in California" by the Daily Journal and one of the "500 Leading Lawyers in America" by Lawdragon, Ambassador O’Brien forged his career as lead trial and appellate counsel in high-profile matters. 

In his commercial litigation practice, Ambassador O’Brien handles class action, entertainment, intellectual property, environmental, business torts, and complex contractual matters in state and federal courts. He is regularly appointed as a mediator, arbitrator, and discovery referee, having served as the Special Master in several of the largest cases in the Central District of California, including MGA v. Mattel ("Barbie v. Bratz"), United States v. Standard & Poors and In re Allergan Securities Litigation. Prior to co-founding the firm in 2016, Ambassador O'Brien was the California managing partner of a national Am Law 200 firm for nearly a decade and an attorney at Skadden, Arps, Slate, Meagher & Flom LLP.

In addition to his litigation and alternative dispute practices, Ambassador O’Brien is one of the country’s leading diplomats and advisors on national security issues. As National Security Advisor, he brought a renewed focus to defense and industrial base issues, orchestrated the historic Abraham Accords in the Middle East, brokered economic normalization between Serbia and Kosovo, and achieved increased cooperation with America’s allies across the Indo-Pacific. Previously, Ambassador O’Brien was the Special Presidential Envoy for Hostage Affairs, during which time he coordinated the government's diplomatic engagements on overseas hostage-related matters and successfully negotiated the return of over 20 hostages and wrongfully detained Americans. 

Ambassador O'Brien was the U.S. Alternate Representative to the 60th session of the U.N. General Assembly and a member of the Cultural Property Advisory Committee. He was the founding co-chairman of the State Department's Public-Private Partnership for Justice Reform in Afghanistan, serving under Secretaries of State Condoleezza Rice and Hillary Rodham Clinton. Ambassador O'Brien was a senior legal officer at the U.N. Security Council in Geneva, Switzerland, and a Major in the U.S. Army Reserve JAG Corps. He was a member of the International Republican Institute delegations that observed the presidential election in the Republic of Georgia in October 2013 and the parliamentary election in Ukraine in October 2014. Ambassador O'Brien was also a Pacific Council on International Policy observer of the 9/11 Military Commission pretrial proceedings in Guantanamo Bay.  

Ambassador O’Brien is the recipient of the National Security Medal, the National Intelligence Distinguished Service Medal, the Department of Defense Medal for Distinguished Public Service, the National Defense Service Medal, and the Kosovo Presidential Medal of Merits. Los Angeles Business Journal has also named Ambassador O'Brien one of the 500 most influential people in Los Angeles. 

To check on Ambassador O’Brien’s availability to speak to your organization, please contact Worldwide Speakers Group at

  • Benchmark Litigation, "Litigation Star"
  • Lawdragon, "500 Leading Lawyers in America"
  • Daily Journal, "Top 100 Lawyers in California"
  • Los Angeles Business Journal, "LA500: The Most Influential People in L.A."
  • Los Angeles Business Journal, "Top Litigators & Trial Lawyers"
  • National Security Medal
  • National Intelligence Distinguished Service Medal
  • Department of Defense Medal for Distinguished Public Service
  • National Defense Service Medal
  • Kosovo Presidential Medal of Merits
Firm News

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Benchmark Litigation

Larson LLP shortlisted for "Firm of the Year"

Larson LLP is one of seven Los Angeles firms recognized as finalists for Benchmark Litigation’s 2021 "Firm of the Year" award.


    University of California, Berkeley School of Law, J.D.

    University of California, Los Angeles, B.A., cum laude


    U.S. Supreme Court
    U.S. Court of Appeals for the Ninth Circuit
    U.S.D.C Central District of California
    U.S.D.C Eastern District of California
    U.S.D.C Northern District of California
    U.S.D.C Southern District of California