Marshall Dennehey, PC

Professional Liability Department

Chair, Appellate Advocacy & Post-Trial Practice Group

John is a member of the firm’s Board of Directors and chair of Marshall Dennehey’s Appellate Advocacy and Post-Trial Practice Group. He has litigated more than 500 appeals in state and federal appellate courts. As litigation counsel, John has represented individuals, insurers, and corporations in some of the most high-profile litigation in recent Pennsylvania history, including dozens of cases with verdicts and settlements in excess of $10 million.

John serves by appointment of the Supreme Court of Pennsylvania as the co-chair of the Court’s Historical Commission and on the Commission on Judicial Independence, a group of state and federal judges, academics, and attorneys who work to promote public awareness of the importance of a strong, independent judiciary in a free society. He also spent six years on the Supreme Court’s Civil Procedural Rules Committee, the last two years as chair, and served on the Board of Governors of the Bar Association of the Third Federal Circuit and as co-chair of the Amicus Curiae Committee of the Pennsylvania Defense Institute. He also serves on the advisory board of Ohlbaum on the Pennsylvania Rules of Evidence (Lexis-Nexis) and regularly speaks at appellate court events and continuing legal education seminars.

American Academy of Appellate Lawyers, Fellow, 2016 Bar Association for the Third Federal Circuit International Association of Defense Counsel, 2018 Pennsylvania Bar Association Pennsylvania Defense Institute, 2008 Pennsylvania Supreme Court, Civil Procedural Rules Committee, 2015-2021; Chair, 2019-2021 Pennsylvania Supreme Court, Historical Commission, Co-Chair, 2023 Pennsylvania Supreme Court, Commission on Judicial Independence, 2024

Princeton University Ph.D. Coursework 1999

University of California, Berkeley M.A. 1998

Duquesne University School of Law J.D. 1993

Indiana University of Pennsylvania B.A. 1990

Under John’s leadership, his practice group has achieved recognition as the Pennsylvania Litigation Department of the Year for Appellate Law in 2024 and 2016, by The Legal Intelligencer and American Lawyer Media.

Chambers USA, Pennsylvania: Litigation: Appellate Law, Band One 2025

AV® Preeminent™ Martindale-Hubbell®

Appellate Practice The Best Lawyers in America© 2024-2025

Top 100 in Pennsylvania Pennsylvania Super Lawyers 2008-2024

Best of the Bar Award Philadelphia Business Journal 2023 and 2018

Influencers of Law Award The Philadelphia Inquirer 2019

John has developed, edited, and co-authored two books on Pennsylvania’s appellate courts -- The Supreme Court of Pennsylvania; Life and Law in the Commonwealth, 1684-2017, was published by the Pennsylvania State University Press in 2018; and Keystone of Justice: The Pennsylvania Superior Court, 1895-1995, was published by the Commonwealth of Pennsylvania in 2000.

John authored “Chief Justice Baer and the Supreme Court’s Tricentennial Anniversary,” 62 Duquesne Law Review 1 (Winter 2024).

He is frequently sought out by regional legal and business media seeking comment on appellate court activity. He regularly provides commentary to reporters at The Philadelphia Inquirer, The Legal Intelligencer, Pennsylvania Law Weekly, GoErie.com., The Pocono Record, and The Tribune Review. Visit his Marshall Dennehey bio for the complete list.