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Sean Morris represents clients in complex commercial litigation, with particular emphasis on mass torts, unfair business practices, and government civil claims. Sean has a proven track record of helping clients navigate high-profile matters and has served as lead defense counsel in several MDL and state Attorney General actions. He is head of the firm's Los Angeles office.

Sean has been at the forefront of defending against public nuisance claims brought by governmental entities against private businesses. Among his significant cases, he successfully tried the California lead pigment litigation, in which public prosecutors asserted that former manufacturers of lead pigment should be held liable for the alleged health hazard created by the existence of lead paint on millions of private residences.

Sean has been named one of the "Top 100 California Lawyers" by the Daily Journal (2019), recognized by The Legal 500 for Product Liability/Mass Tort and IP/Copyright (2011, 2021), and selected as a BTI Client All-Star for Commercial Litigation (2020).

In addition to his commercial matters, Sean maintains a robust pro bono practice, including representing military sexual assault survivors and pursuing impact litigation on behalf of immigrant families who were separated at the border by the U.S. government under its "Zero Tolerance" policy.


  • Major oil and gas company in litigation brought by government entities and private landowners claiming that historic exploration activities in Louisiana have contributed to coastal land loss.
  • Major oil and gas company in national litigation brought by government entities claiming that the marketing and sale of oil and gas products has led to climate change.
  • Atlantic Richfield as lead national counsel defending against claims brought by government entities and individual plaintiffs around the country alleging injuries arising from lead paint on residential walls, including as co-trial counsel in successfully defeating public nuisance claims brought by California prosecutors seeking a US$1.1 billion fund to abate all residential properties that contain lead paint.
  • Dunkin' in class actions alleging false and misleading advertising regarding content of donuts and other products.
  • BP/Atlantic Richfield as co-lead counsel defending against multiple personal injury, environmental, and property damage lawsuits by residents living near former lead manufacturing facility.
  • BP as lead defense counsel in multidistrict class action in which plaintiffs alleged fraud and violation of state unfair business practice statutes based on the sale of gasoline by the volumetric gallon instead of using advanced temperature adjustment technology.
  • Kroger in defending putative class action alleging unfair business practices for representations regarding the nutritional content of food products.
  • Major Pharmaceutical Company as co-lead national counsel in a series of cases (including those combined within an MDL) brought by government prosecutors, third-party payors, and private individuals alleging fraudulent marketing and improper distribution of opioids for chronic pain and seeking billions in abatement costs, damages, restitution, and civil penalties.
  • Top mobile gaming app developer in defeating putative nationwide class action suit alleging that game constituted illegal gambling in violation of consumer protection laws and other state statutes. Mason v. Machine Zone Inc., 140 F.Supp.3d 457 (D. Maryland 2015).
  • VeriSign in putative nationwide MDL class actions regarding alleged improper advertising practices for content downloaded directly to smartphones.


The Chemical Compound, Summer Edition
Environmental Edge: Climate Change & Regulatory Insights
The Chemical Compound—August 2021
The Chemical Compound—May 2021
The Chemical Compound—February 2021
Legal Updates on High Priority Chemicals and Important Chemical-Regulatory Developments
The Chemical Compound—October 2020
Legal Updates on High Priority Chemicals and Important Chemical-Regulatory Developments


The Legal 500 U.S.
Product liability, mass tort and class action: toxic tort - defense (2021)
Recommended for Intellectual Property: Copyright (2011)
BTI Client Services
"BTI Client Service All-Star"–Complex Commercial Litigation (2020)
Daily Journal
"Top 100 Lawyers in California" (2019)



  • J.D., University of California, Los Angeles, School of Law, 1996
  • B.A., University of California, Berkeley, 1993


  • California
  • New York


  • Member, Law360's 2023 California Editorial Advisory Board
  • Fellow, American Bar Foundation
  • Founder and current board member, Reading to Kids, a Los Angeles-based nonprofit organization