Seamus C. Duffy

Partner Philadelphia
Phone: (215) 988-2440 (215) 988-2440


Seamus C. Duffy leads the firm’s class actions practice. He has a depth of experience representing companies with interstate business and operations in managing overlapping federal and state private class and mass actions and related government enforcement proceedings. A frequent speaker on issues relevant to the defense of class actions, Seamus regularly serves as national counsel defending consumer class actions for Fortune 100 companies, both in federal multidistrict litigation proceedings and their state court equivalents. Seamus is also a nationally recognized thought leader on privacy law and litigation and frequently advises in-house counsel in an array of industries on emerging risks, regulatory and compliance issues in the privacy arena.


Seamus has been an architect of strategies to defeat class certification and has obtained favorable results across the country on a host of claims, including mass tort product liability, unfair competition, consumer protection and breach of contract/warranty claims. He is also a leading appellate advocate on issues related to class certification and consumer protection laws.

  • Won a First Amendment case on behalf of CTIA challenging a first-of-its-kind ordinance in the U.S. that mandated that retailers publicize information about the potentially dangerous effects of cellphone uses. CTIA – The Wireless Association v. City and County of San Francisco, Calif., case number 11-17773 (9th Cir.).
  • Representing a company in a privacy class action MDL challenging targeted advertising activity under the Video Privacy Protection Act. In re: Vizio Inc. Consumer Privacy Litigation, MDL No. 2693 (C.D. Cal.).
  • Defeated a putative class action in California federal court alleging that national broadband carrier violated the Consumer Fraud and Abuse Act in connection with the provision of public wifi services. Toyer Grear, et al. v. Comcast Corp., 4:14-cv-05333 (N.D. Cal.).
  • Spearheaded the decade-long defense of precedent-setting “bet-the company” litigation involving claims against the wireless industry that wireless phones cause brain cancer. Defeated the original wave of class actions, alleging that the sale of phones without headsets was actionable under state law, over a 10-year period through the state and federal courts. See, Farina v. Nokia, 578 F.Supp. 2d 740, 770 (2008), aff’d 625 F.3d 97 (3d Cir. 2010)).
  • Serves as coordinating counsel for a leading national energy company defending class and mass action claims by landowners and other owners of royalty interests in natural gas based on claims of antitrust conspiracy and monopolization, including claims under the Racketeer Influenced and Corrupt Organizations Act (RICO). A&B Campbell Family LLC v. Chesapeake Energy Corporation, et al., No. 3:15-cv-340 (M.D.Pa.)
  • Defeated class action involving claims under the Cable Communications Privacy Act, Illinois Cable and Video Customer Protection Law, and California Customer Records Act, California Penal Code § 637.5. Bayer, et al. v. Comcast Cable Communications, LLC, No. 1:12-cv-08618 (N.D. Ill.).
  • Defended a national broadband carrier against first-of-its-kind attempt to use the class action device to impose liability based on Net Neutrality principles. In re: Comcast Corp. Peer-to-Peer (P2P) Transmission Contract Litigation, 2:08-md-01992 (E.D. Pa.).
  • Defending Telephone Consumer Protection Act (TCPA) class actions for leading retail, communications and energy companies nationwide. Grant v. Commonwealth Edison Company, No. 1:13-cv-8310 (N.D. Ill.); Chimeno-Buzzi, et al. v. Hollister Co., et al., No. 1:14-cv-23120 (S.D. Fla.).


Chambers USA, Litigation: General Commercial - Pennsylvania (2018)
Recognized as a “Litigation Star” by Benchmark Litigation

Awards Methodology (


Bar Admissions

  • Pennsylvania


  • Villanova University School of Law, J.D., 1987, summa cum laude
  • Villanova University, B.A., 1984


  • National Institute for Trial Advocacy