Sean Gallagher is an accomplished trial lawyer with experience across a broad range of complex commercial litigation matters. Most of Sean's representations have been for major U.S. and international companies in cases involving intellectual property (including patent infringement and Lanham Act claims), trade secret misappropriation, product liability, accountant liability, toxic tort, and breach of contract.
Notably, Sean served as lead trial counsel for Ethicon/Johnson & Johnson in a lawsuit claiming that pelvic mesh medical devices made by a J&J subsidiary caused personal injuries. The three-week jury trial resulted in a complete defense verdict in the Philadelphia Court of Common Pleas.
Sean achieved a notable victory in an environmental tort case alleging more than $1 billion in personal injury and property damage arising from claims of a "cancer cluster" near the facility of Pratt & Whitney, an aerospace manufacturer facing the lawsuit. The case ultimately resulted in summary judgment on the personal injury claims.
Sean has also worked on a variety of other matters ranging from Gore v. Bush, where he was part of the Bartlit Beck team that represented President Bush at the trial court level, to Newsome v. McCabe, where he helped obtain compensation for a man wrongfully convicted of murder.
Sean is a nationally recognized attorney. He was named Benchmark Litigation's 2026 Trial Lawyer of the Year and is ranked by Chambers USA as one of the leading litigators in Illinois. Chambers noted his "expertise handling large class actions, including those with product liability and breach of fiduciary aspects" and quoted sources calling him an "effective courtroom advocate and strategist" and describing his lawyering as "measured, focused and persuasive."
Sean has won numerous awards, including being named a "Notable Litigator & Trial Attorney" by Crain's Chicago Business (2023), a "Leading Litigator in America" by Lawdragon, a "Stand-out Lawyer" by Reuters, and a "Litigation Star" and "Top 100 Trial Lawyer" by Benchmark Litigation.
Sean joined the firm in 1996 directly from a clerkship for Justice Sandra Day O'Connor of the Supreme Court of the United States, before which he served as law clerk to Judge Alex Kozinski of the United States Court of Appeals for the Ninth Circuit.
Sean graduated from the University of Michigan Law School magna cum laude and received his B.A. from the University of Michigan with Highest Distinction.
- Year joined firm: 1996
- Appellate
- Class action
- Commercial disputes
- Environmental
- Intellectual property
- Product liability and recall
- Accounting
- Aviation
- Financial services
- Industrials
- Pharmaceutical and life sciences
- Technology and telecommunications
- J.D., magna cum laude, University of Michigan Law School (1994)
- B.A., with Highest Distinction, University of Michigan (1990)
- Illinois