Key Experience

  • More than 30 years of experience representing companies in class actions in federal and state courts.
  • Has effectively shut down efforts of prolific, professional plaintiffs in improperly leveraging the class action device.


Seamus Duffy brings a depth of knowledge and experience and a thoughtful, strategic approach to bet-the-company litigation. In 2018, Chambers USA reported that he “is hugely popular among clients, who consider him a ‘good strategist with terrific diplomatic skills.’ He comes highly recommended for his ability to handle class actions. He is particularly well known for his representation of clients in the communications industry.”

Representative Work

  • Successfully represented the wireless industry in the 9th Circuit Court, challenging a first-of-its-kind ordinance that required retailers to publicize the San Francisco government’s opinions regarding the alleged human health effects of mobile phone usage.
  • Defends against federal and state laws related to communications, data and privacy. These statutes include the Telephone Consumer Protection Act (TCPA), Cable Communications Policy Act (CCPA), Video Privacy Protection Act (VPPA) and Biometric Information Privacy Act (CIPA).
  • Successfully defended against a trio of claims brought under the California Unfair Competition Law (UCL), False Advertising Law (FAL) and Consumers Legal Remedies Act (CLRA).