Sean focuses primarily on complex commercial and product liability litigation. He has represented clients in the chemical, consumer product, pharmaceutical, medical device, food and fragrance, and industrial products sectors when they faced significant product liability and mass tort claims, including putative class actions. He has litigated cases in federal and state courts in dozens of jurisdictions.

Sean is the former office managing partner of Shook’s Philadelphia office, which he founded in 2012, and now has grown to more than 20 attorneys. He joined Shook after practicing as a partner with Dechert LLP, where he chaired the product liability and mass torts group for more than 10 years. Sean served for nearly a decade as lead counsel for a flavorings company in the diacetyl mass tort litigation, as trial counsel in numerous diet drug trials and as legal strategist on the team that secured a defense jury verdict in the first tobacco medical monitoring trial—a class action involving 250,000 plaintiffs in West Virginia. He also acted as lead counsel in complex commercial litigation arising from a textile mill fire and in a putative class action alleging the release of chemicals at a North Carolina pharmaceutical facility. 

Sean serves as lead counsel for a major animal health company in litigation, including matters brought by numerous chicken farms alleging that the client’s poultry vaccine was defective, matters by ranchers asserting that a vaccine for Bovine Respiratory Disease was ineffective, matters challenging the client’s flea and tick medication for pets, a matter involving vaccines administered to pregnant cows, and matters alleging that an equine antibiotic injured hundreds of horses. His work led to the denial of class action status in the horse matters, and the application of the preemption doctrine to multiple claims under APHIS regulations in the cattle matters. His briefing also led to an important decision confirming that the learned intermediary doctrine applies to prescription animal drugs regulated by the FDA. Sean crafted the successful motion to dismiss a federal court product liability action in which plaintiffs alleged that their cattle died as a result of his client’s multi-purpose vaccine. The motion argued that the Idaho state law failure to warn and design defect claims were preempted under the Viruses, Serums, Toxins, and Analogous Products Act (VSTA) and the Animal and Plant Health Inspection Service’s (APHIS) promulgation of regulations governing vaccine products.

Sean served as co-lead national counsel for a pharmaceutical company in the testosterone replacement therapy mass tort, In Re: Testosterone Replacement Therapy Products Liability Litigation, No. 14-1748 (N.D. Ill.). He represents a pharmaceutical maker in multiple product matters involving its class-leading drug for nervous systems disorders. Sean also provided MDL guidance and legal strategy for the team that secured summary judgment and dismissal of all pending claims in mass tort litigation alleging a prescription drug caused birth defects in the children of mothers who used the drug when pregnant. He has drafted amicus appellate briefs on MDL policy issues for organizations such as the Product Liability Advisory Council. He served as a Team Leader in developing the influential Guidelines and Best Practices for Large and Mass-Tort MDLs (Second Edition). In addition to his product liability work, which has also included asbestos, forklifts, isocyanates, PCBs and other manufacturing and consumer goods, Sean has represented multiple clients in putative class actions raising state consumer fraud, unfair or deceptive trade act claims, and has assisted clients with significant commercial disputes. He currently acts as the relationship partner for a pharmaceutical client, providing product liability strategic advice and litigation mitigation guidance.

A trusted advisor on complex commercial issues, Sean has counseled clients on ways to assess and mitigate potential litigation risks in the mergers and acquisitions context as well as those arising from client entry into new geographic or product markets. Frequently asked by clients to monitor ongoing litigation as plaintiffs add new classes of defendants, Sean has advised corporations on U.S. labeling regulations and emerging tort issues, such as those involving the chemical BPA in food containers and the potential product liability issues related to a new technology for cord blood storage. He has also advised clients in the adhesives industry on formaldehyde exposure issues and consumer product clients on warnings and labels.

Sean has been ranked annually among the top product liability lawyers by Chambers USA, a referral guide to leading lawyers in the United States based on the opinions of their peers and clients. Chambers has praised Sean for his "fantastic knowledge of class action law and procedure," describing him as a “calm and organized” lawyer who “continues to deliver high quality work in the pharmaceutical area.” Clients have also noted about Sean, "He can help develop arguments and responses on the technical aspects of any litigation." A recent edition of Chambers states that Sean "is well regarded for his strength in product liability litigation. He is particularly experienced in pharmaceutical MDLs and is also highly respected in the medical device and consumer product sectors." The Best Lawyers in America has also recognized Sean for product liability and mass tort litigation; he has been named twice as the “Lawyer of the Year” for mass torts and class action defense in the Philadelphia region. The Legal 500 United States recommended his work in product liability and mass tort defense in the areas of toxic tort and consumer products (including tobacco); and Who's Who Legal: The International Who’s Who of Product Liability Defence Lawyers named him a leading product liability defense attorney. His class action and litigation experience has also been featured in several editions of Super Lawyers.

Sean is an American Bar Foundation fellow and an elected member of the American Law Institute, the leading independent organization in the United States producing scholarly work to clarify, modernize and otherwise improve the law. He formerly served on Law360's Product Liability Editorial Advisory Board and previously chaired the Mass Torts and Class Actions Subcommittee of  DRI (Defense Research Institute), a national organization of more than 22,000 defense trial lawyers and corporate counsel. Sean served for a decade as Lecturer-in-Law at the University of Pennsylvania Law School teaching toxic torts and product liability law, and served for a time as the Thomas O'Boyle Honorary Lecturer in Law.


Publications and Presentations

Co-Author: “Consent” to Jurisdiction by Registering to Do Business, American Bar Association Product Liability Litigation newsletter, Summer 2022 (with Joseph Blum). 

Sean is the author of the widely read blog Mass Tort Defense, which focuses on the defense of complex commercial litigation and significant product liability matters.

Co-Author: I Do? Mallory v. Norfolk Southern Railway Company and the General Jurisdiction Consent Battle, Mealey's Litigation Report, February 23, 2022 (with Joseph Blum). 

Co-Author, Important Product Liability Practice Trends To Watch In 2022, Law360, February 8, 2022 (with Hildy Sastre).

Team Leader, Standards and Practices for Large and Mass-Tort MDLs, 3rd Edition, George Washington University Law School, 2022. 

Co-Author, “Medical Monitoring Class Actions,” A Practitioner’s Guide to Class Actions, American Bar Association, 2021.

Presenter, Motions to Strike Class Action Allegations: Recent Trends, Best Practices, Strafford Live CLE Webinar, August 17, 2021.

Presenter, Motions to Strike Class Allegations, Strafford Live CLE Webinar, July 7, 2020. 

Presenter, Defeating Class Actions Post-Certification: Procedural and Substantive Strategies, Strafford Live CLE Webinar, June 24, 2020.

Presenter, Deploying Rule 23(d)(1)(D) Motions for Class Allegations Pre-Certification, Strafford Live CLE Webinar, May 9, 2019.

Team Leader, Standards and Practices for Large and Mass-Tort MDLs, 2nd Edition, Bolch Judicial Institute, Duke Law School, 2018. 

Presenter, Defeating Class Actions, Strafford Live CLE Webinar, December 18, 2018.

Joseph Blum, John Lyons & Sean Wajert, Corporations: Are You Voluntarily Consenting to General Jurisdiction in Pennsylvania?, Westlaw Journal: Corporate Officers & Directors Liability, July 10, 2017. 

Moderator, Inside View: Legal and Ethical Considerations for In-House Counsel, Third Annual Life Sciences Legal Summit, September 21, 2016.

Presenter, Products Liability Litigation: Addressing Other Similar Incidents and Lack of Prior Accidents Evidence, Strafford Live CLE Webinar, September 6, 2016.

Presenter, Daubert/Frye Motions in Product Liability Litigation, Strafford Live CLE Webinar, June 10, 2015. 

Author, Combating Commonalities in Toxic Tort Class Actions, Law360, May 8, 2015.

Editor, The Class Actions and Mass Torts Answer Book (PLI 2015).

Author, Noteworthy Product Liability Decisions Of 2012: Part 1, Law360, Jan. 9, 2013. 

Author, A Criminal Act Severs The Chain Of Causation, Law 360, Aug. 21, 2012.