Harold C. Trimmer


Harold Trimmer’s practice focuses on professional liability, general civil litigation, as well as white-collar criminal defense and related matters.

Mr. Trimmer has represented professionals in liability matters, including the defense of law firms, lawyers, and accountants in malpractice actions. Mr. Trimmer is also experienced in a variety of other general litigation matters, including contract disputes, embezzlement cases, and fraud matters. He has also authored and argued appeals before the California Court of Appeal and the Ninth Circuit.

Mr. Trimmer has also defended individuals in state and federal criminal actions, including political corruption investigations, military procurement fraud, investment fraud, and other complex criminal matters.

A native of Las Vegas, Mr. Trimmer graduated from Georgetown University’s Edmund A. Walsh School of Foreign Service with a bachelor of science in foreign service in 2002. In 2006, he received his J.D. from the University of San Diego, School of Law. During his undergraduate studies, he researched international trade policy at the Center for Strategic and International Studies and was a policy advisor on e-commerce issues at the Office of the United States Trade Representative. Prior to attending law school, he was the marketing director for a Santa Barbara internet startup.

Prior to joining Klinedinst, Mr. Trimmer was an associate at the litigation firm Coughlan, Semmer, Fitch & Pott and its predecessor Coughlan, Semmer & Lipman. In 2013, he was named one of San Diego’s Top Young Attorneys by The Daily Transcript. He is active in the San Diego Defense Lawyers and an alumnus of the Louis M. Welsh Inn of Court.



San Diego
619.238.8707 Fax


Harold C. Trimmer, Esq.


  • California (2006)
  • U.S. District Court, Southern District of California (2006)
  • Ninth Circuit Court of Appeals (2013)
  • U.S. District Court, Central District of California (2014)