Sean A. Petterson

Sean A. Petterson is a partner in Lieff Cabraser’s New York office. He is a member of the firm’s cybersecurity/data privacy practice group. As a member of that group, he focuses on nationwide data breach class actions. He was recently appointed to the Plaintiffs’ Steering Committee in the nationwide In re: Snowflake, Inc., Data Security Breach Litigation. Additionally, he works on the pending nationwide data breaches against Marriott and Quest Labs, with a particular focus on experts. Along with his data breach work, Mr. Petterson represents truck drivers in two proposed class actions brought under the Illinois Biometric Information Privacy Act against two technology providers.

Mr. Petterson is also a member of the firm’s securities practice group. Sean’s successful cases include a shareholder derivative action against The Boeing Company’s officers and directors [hyperlink: https://lieffcabraser.com/securities/boeing/ ]. Sean represented Co-Lead Plaintiffs the New York State Comptroller Thomas P. DiNapoli, as trustee of the New York State Common Retirement Fund, and the Fire and Police Pension Association of Colorado in the action alleging breach of fiduciary duty in connection with the board of directors’ oversight of the 737 MAX’s design and development. In February 2022, the Delaware Chancery Court approved a settlement comprised of a $237.5 million cash payment and extensive corporate governance reforms.

Sean was also a member of the Lieff Cabraser team representing Co-Lead Plaintiff Fire and Police Pension Association of Colorado in a shareholder derivative action against Wells Fargo’s current and former officers and directors [hyperlink: https://lieffcabraser.com/securities/wells-fargo/ ] arising from the illicit sales practices scandal. The case settled for a $240 million cash payment and corporate governance reforms in April 2020. The settlement represents the largest insurer-funded derivative settlement in history.

Sean is also a member of the firm’s consumer protection practice group, where he has helped successfully resolve cases brought under the Telephone Consumer Protection Act [hyperlink https://lieffcabraser.com/consumer/tcpa-cases/ ]. And, finally, Sean is currently representing retired pastors in the In Re: AME Church Employee Retirement Fund Litigation, MDL No. 3035.

Sean has been named “Ones to Watch” by Best Lawyers from 2021-2025 and a Rising Star for the New York Metro Area by Super Lawyers from 2021-2024. He has spoken at conferences regarding data breach litigation, with a particular focus on Article III standing and damages.

Prior to joining Lieff Cabraser, Sean was an associate at Boies Schiller Flexner, LLP from 2015-2018. He is a 2015 graduate from New York University School of Law with a Juris Doctor, where he was a Robert McKay scholar and a Senior Quorum Editor for the Journal of Legislation and Public Policy. Sean also graduated summa cum laude from Brandeis University with a B.A. in both History and American Studies.

Honors & Awards

•“Ones to Watch,” Best Lawyers, 2021-2026
•“Lawdragon 500 Leading Plaintiff Consumer Lawyers in America,” Lawdragon, 2025, 2026
•“Rising Star for New York Metro Area,” Super Lawyers, 2021-2025

In the News

•February 17, 2026
30 Lieff Cabraser Attorneys Recognized as Lawdragon “500 Leading Plaintiff Consumer Lawyers” for 2026
•October 30, 2025
21 Lieff Cabraser Attorneys Selected as 2025 New York Metro Super Lawyers and Rising Stars
•August 21, 2025
36 Lieff Cabraser Lawyers Named to 2026 Best Lawyers Listings
•February 28, 2025
33 Lieff Cabraser Attorneys Recognized as Lawdragon “500 Leading Plaintiff Consumer Lawyers” for 2025
•October 25, 2024
18 Lieff Cabraser Attorneys Selected as 2024 New York Metro Super Lawyers and Rising Stars