Brian Hennigan is a resident partner in the Los Angeles office of Irell & Manella LLP. He is a partner in the firm’s litigation workgroup and heads the firm’s white collar crime defense practice. He also serves as a member of the firm's executive committee.

Mr. Hennigan’s practice specializes in complex litigation, with an emphasis on white collar crime defense. He has been widely recognized for his professional excellence, including listings in the following publications: The Best Lawyers in America - past ten years; Chambers USA America’s Leading Lawyers for Business Guide (Top Ranking), 2003-2008; California Lawyer (State Bar publication) "Best in the West" 2004; Daily Business Journal "Best Trial Attorneys" 1999; and Los Angeles Magazine's Southern California "Super Lawyers" - each year of publication.  In 2007 and 2008, he was also selected as one of the "Top 100 Lawyers” in Southern California by Los Angeles Magazine.

Mr. Hennigan has served as lead trial counsel in more than 40 trials and as lead appellate counsel in numerous cases before the United States Court of Appeals. He has tried cases in state and federal courts, represented clients under investigation by state and local law enforcement, and represented clients in forums ranging from federal grand jury investigations to Senate investigations.  

Before joining Irell & Manella, Mr. Hennigan was a federal prosecutor, serving as the Deputy Chief for the Government Fraud and Public Corruption Section of the United States Attorney’s Office in Los Angeles and was the head of the Medicare Fraud Task Force in that office as well. In appreciation for his contribution to federal law enforcement, he was awarded the Special Achievement Award from the Department of Justice, as well as awards from various investigating agencies, including the following: Office of the Inspector General, Health and Human Services, the Criminal Investigation Division, Internal Revenue Service, the Federal Bureau of Investigation, and the Defense Criminal Investigative Service.

Mr. Hennigan is married and the father of John, Kelly and Elise Hennigan.

Representative Matters

• Mr. Hennigan successfully represented a Brazilian bank in a racketeering action against a former bank employee and a group of international con men, obtaining in 2005 a court order for $212 million on behalf of his clients.
• Mr. Hennigan successfully represented (at trial in 2005) Paychex (a Fortune 100 company) in a lawsuit by a licensee seeking over $50 million in damages for alleged fraud, breach of contract, and unfair competition. The court rejected the plaintiff’s fraud and unfair competition claims, ultimately awarding the plaintiff damages of $30,000.
• Mr. Hennigan successfully defended the president of a motion picture studio on charges of tax fraud felonies in a month long jury trial in 1997.
• Mr. Hennigan has represented numerous companies and individuals in investigations by the SEC, the IRS, the FBI and other federal agencies. Many of these investigations were concluded with the government reaching the decision not to prosecute.

Professional Activities

• Mr. Hennigan has been recognized as a leader in the federal and specialized bar associations. He is the immediate past President of the Federal Bar Association, Los Angeles Chapter (2004-2005), and has served on the Board of Directors for the Federal Bar Association for the past eight years. He served as the co-chairman of the American Bar Association, White Collar Crime Committee, West Coast Region for the years 2004-2006, and he has served on the Board for this group for the past ten years. He has previously served as the co-chairman for the ABA, Health Care Fraud Section and is currently the Vice Chair for the ABA, White Collar Criminal Defense Section. He is also a fellow of the American College of Trial Lawyers.
• Mr. Hennigan has authored over fifteen articles on issues related to his practice area and has lectured for the American Bar Association, the Federal Bar Association, the Los Angeles County Bar Association, and to local law schools.

Bar & Court Admissions

• 1976, Illinois
• 1979, California