Robert C. O’Brien, U.S. Ambassador can help with mediation and arbitration through Signature Resolutions in Los Angeles.

Century City | Los Angeles | Virtual Services

Robert C. O’Brien, U.S. Ambassador (Ret.)

Mediator | Arbitrator | Special Master

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“I know that at Signature Resolution, I can use my experience as a lawyer and diplomat to assist parties to achieve fair and satisfactory solutions to their disputes.”

Case Administrator

Practice Areas

  • Business / Commercial
  • Class Action
  • Employment
  • Entertainment
  • General Liabilities & Malpractice
  • Real Estate
  • Securities
  • Wage & Hour


  • J.D., Boalt Hall School of Law, UC Berkeley
  • B.A., cum laude, Political Science, UCLA


A former U.S. ambassador and the 28th National Security Advisor, Robert C. O’Brien co-founded the firm with Stephen G. Larson and is a partner emeritus at Larson LLP. Robert 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, Robert forged his career as lead trial and appellate counsel in high-profile matters. 
In his commercial litigation practice, Robert 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, Robert was the California managing partner of a national Am Law 200 firm for nearly a decade and, earlier in his career, was an associate at Skadden, Arps, Slate, Meagher & Flom LLP. 
In addition to his litigation and alternative dispute practices, Robert 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, Robert was the Special Presidential Envoy for Hostage Affairs and held the personal rank of ambassador. As SPEHA, he coordinated the government’s diplomatic engagements on overseas hostage-related matters and successfully negotiated the return of over 25 hostages and wrongfully detained Americans. 
Robert 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. Robert 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. Robert was also a Pacific Council on International Policy observer of the 9/11 Military Commission pretrial proceedings in Guantanamo Bay. 
Robert 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. 
The National Museum of the Surface Navy named Robert the recipient of the 2021 Freedom of the Seas Award. Following the signing of the Abraham Accords in 2020, a tree was planted on behalf of the State of Israel at the John F. Kennedy Memorial Forest in the Hills of Jerusalem in honor of O’Brien. In 2019, O’Brien received the Dr. Miriam and Sheldon Adelson Award for the Defense of America and Israel. The U.C. Berkeley School of Law presented O’Brien with the Stefan A. Riesenfeld Memorial Award for outstanding contributions to the field of international law in 2011. The Los Angeles Business Journal also named O’Brien one of the 500 most influential people in Los Angeles. 
To check on Robert’s availability to speak to your organization, please contact Worldwide Speakers Group at [email protected] 


  • Of Counsel, Larson LLP (2021–present)
  • National Security Advisor, United States (2019–2021)
  • Special Envoy for Hostage Affairs, U.S. Department of State (2018–2021)
  • Founding Partner, Larson O’Brien (2016–2019)
  • West Coast Managing Partner, Arent Fox LLP (2007–2015)
  • Member, U.S. Cultural Property Advisory Committee (2008–2011)
  • Co-Chairman, U.S. Department of State Public-Private Partnership for Justice Reform in Afghanistan (2007–2011)
  • U.S. Alternate Representative, 60th Session of the UN General Assembly (2005–2006)
  • Team Leader, UN Security Council, Government Claims Section, (Compensation Commission) (1996–1998)

Professional Achievements and Memberships

  • Dr. Miriam and Sheldon Adelson Award for Defense of America and Israel, The Zionist Organization of America (2019)
  • Stefan A. Riesenfeld Memorial Award for contributions to the field of international law, Boalt Hall School of Law, U.C. Berkeley (2011)
  • Marc Fleischaker Pro Bono Award for contributions to the public good, Arent Fox LLP (2011)
  • Erwin Chemerinsky Defender of the Constitution Award, Federal Bar Association (Riverside Chapter) (2009)
  • Outstanding Lawyer Award, J. Reuben Clark Law Society (Los Angeles Chapter) (2009)
  • Cardinal Newman High School Alumni Scholarship/Leadership Award for Public Service (2006)