Brien O’Connor is an accomplished trial lawyer who has also negotiated some of the most significant corporate criminal and civil resolutions in the country. Widely recognized as one of the nation’s leading white collar defense lawyers, Brien has been characterized by Chambers USA as “a hugely experienced and well-respected litigator who delivers both quality service and quality result.”

Brien focuses his practice on representing corporations and individuals in government investigations and litigation, including civil False Claims Act cases. He regularly counsels clients on matters involving alleged health care fraud and abuse, securities fraud, tax crimes, export law violations, and other fraud and corruption. He has successfully litigated numerous civil and criminal cases, including multi-district civil litigation and False Claims Act cases. Brien also conducts internal investigations and compliance reviews for corporate clients.

A former Assistant U.S. Attorney for the District of Massachusetts and Chief of that office’s Public Corruption and Special Prosecutions Unit, Brien spent 10 years investigating and prosecuting cases involving complex securities, health care, insurance, tax and bank fraud; drug trafficking, money laundering and RICO violations; and public corruption and other federal crimes. Brien has successfully tried numerous cases to juries and successfully handled several federal appeals.

Brien has been a member of the firm’s Policy Committee since 2013 and is former co-head of the firm’s Government Enforcement practice group.

Areas of Practice