About Sean T
Sean T Prosser began his academic path at the University of Pennsylvania, where he completed a Bachelor of Arts in English in 1986. He went on to New York Law School and earned his J.D. in 1992. Those formative years combined a humanities background with legal training and set the stage for a career that has crossed public enforcement and private practice.
Prosser’s legal career started in federal enforcement. In 1990 he served as a law clerk in the Office of Broker-Dealer Enforcement in New York for the U.S. Securities and Exchange Commission. He moved to the SEC’s Los Angeles Office of Enforcement in 1992 and worked there as a lawyer. After that period in government service, he entered private practice and joined Gilchrist & Rutter, P.C. as an associate in 1994. He later became an associate at Brobeck, Phleger & Harrison in 1996.
Over the next two decades Prosser advanced through a sequence of senior roles at large firms. He served as a principal at Fish & Richardson in 2003. Two years later he became a partner at Morrison & Foerster LLP in 2005. In 2014 he took on a partner role at Perkins Coie LLP. Records indicate he joined Mintz Levin in 2019 and remains associated with that firm in its offices listed for Los Angeles and other locations.
Prosser is admitted to practice in California and before the Ninth and Eleventh U.S. Courts of Appeal. His early work at the SEC’s broker-dealer enforcement office and the Los Angeles enforcement office provided direct exposure to regulatory investigations and enforcement processes. In private practice he has held practice and leadership positions across firms known for handling complex litigation, regulatory and appellate work. He also maintains membership in the Association of SEC Alumni, reflecting continued ties to the enforcement community.
Colleagues describe a lawyer who has shifted smoothly between the public and private sectors. He has spent time advising and litigating in environments that demand an understanding of enforcement mechanics and appellate procedure. As of 2026 he is working at Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C., and his current practice concentrates on matters stemming from securities enforcement, regulatory compliance, and appellate litigation.
