Mark Harris leads the White Collar Defense & Investigations Group and co-heads the Appellate Group. A former federal prosecutor and U.S. Supreme Court law clerk, Mark represents companies and individuals in complex litigation and high-stakes matters.
His appellate work spans intellectual property, labor relations, constitutional, and administrative law. Since 2017, he has represented the Financial Oversight and Management Board for Puerto Rico, achieving a major victory in the Supreme Court in 2023. Mark is a Fellow of the American Academy of Appellate Lawyers and a past American Lawyer Litigator of the Week.
Mark also handles financial crime and civil enforcement cases, drawing on his experience as an Assistant U.S. Attorney for the Southern District of New York, where he specialized in fraud. He is a noted expert on criminal sentencing and has been on the Board of Editors for the Federal Sentencing Reporter for over 25 years.
As the editor and lead author of “Principles of Appellate Litigation: A Guide to Modern Practice,” he offers invaluable insights into appellate practice. Mark frequently lectures on criminal and appellate law and has been featured in various media outlets.
Mark is a graduate of Harvard College and Harvard Law School and has clerked for U.S. Supreme Court Justices John Paul Stevens and Lewis Powell, Jr. He also serves on the Board of Trustees for the National Museum of Mathematics.
