G. Mark Thompson

As President and CEO of Marshall Dennehey, Mark is responsible for the day-to-day management and business strategy of the firm which consists of 500 attorneys operating out of 19 offices throughout Pennsylvania, New York, New Jersey, Connecticut, Delaware, Ohio and Florida. He was elected to the position in December of 2017 after serving more than three years on the Executive Committee and a decade on the Board of Directors. He succeeded Tom Brophy who served in the role for 13 years.

Mark is joined by a management team comprised of two other senior executives, a Board of Directors, managing attorneys from every office, practice group supervisors, administrative directors and over 1,000 employees who combine their talents to develop and implement the strategies and achieve the objectives of the firm and its clients.

Prior to moving to the firm's Philadelphia headquarters in 2014, Mark also served as the regional managing attorney for its four Florida offices. A Florida native, it was there he built a reputation as a 'go to' attorney advising Fortune 500 clients in high profile, high exposure and often crisis situations. During his career he has handled matters that attracted international media attention, are the subject of books, a documentary film and in one instance a hearing before the US House of Representatives in Washington DC, at which Mark represented one of the corporations testifying.

Mark has more than 30 years of experience in the legal profession, is rated AV Preeminent by Martindale Hubble, was recognized in 2006, 2007, 2013 and 2014 as a Florida Super Lawyer and in 2012 as one of Florida's Legal Elite by Florida Trend magazine. He is admitted to practice before the Florida Supreme Court, the United States Court of Appeals for the Eleventh Circuit and the United States District Court for the Middle District of Florida. He has tried cases in county, circuit, and federal courts and argued before the District Courts of Appeal. In 2012 he also became licensed to practice in Pennsylvania.

Prior to attending law school, Mark spent two years working as an insurance adjuster. The experience continues to inform his understanding of the critical needs of claims professionals.

His civic activities include serving on the Board of Directors of Christian Legal Clinics of Philadelphia, a legal aid organization assisting the disadvantaged, whose north Philadelphia clinic was started and is staffed every month by Mark and his colleagues from Marshall Dennehey. Mark also has served on the Grants Committee of the Philadelphia Bar Foundation.

Honors & Awards

•AV Preeminent by Martindale-Hubbell
•Florida Super Lawyers (2006-2007, 2013-2014)
•Florida Trend Magazine's Florida Legal Elite, 2012
•Pennsylvania Super Lawyers (2018-2022)

Classes/Seminars Taught

•The Best Offense is a Good Defense: Managing Liability Claims in Today's Litigious Environment, Business Insurance Webinar, August 12, 2015
•The Claim Management Link: Interplay Between Risk Tolerance, Operational Structure, Litigation and Claim Outcomes, CLM Annual Conference, March 2015
•Florida Premises Liability - Investigation and Defense
•Florida Liquor Liability
•Spoliation of Evidence

Published Works

•'Experience Is the Best Teacher for Lateral Moves,' The Legal Intelligencer, Top Laterals Supplement, February 24, 2015
•'Protective Orders: Sword and Shield in the War of Discovery,' 12:3The American Journal of Trial Advocacy, Summer 1989

Media Commentary

•''If Only We Had Full Staffing': This Legal Sector is Spread Thin, but Negotiating Higher Rates,' American Lawyer and The Legal Intelligencer, August 15, 2024
•'For The Defense: Insurers' Cost-Cutting Mindset Strains Relationship With Defense Counsel,' cover story, Best's Review, May 2024
•'Pa.'s Second Hundred Firms Saw Modest Gains in 2021,' The Legal Intelligencer, May 24, 2022
•'Marshall Dennehey Cuts Ribbon on New Haven Office,' The Legal Intelligencer and Connecticut Law Tribune, February 28, 2022
•'The Way Back: How Law Firms Are Planning for Post-COVID Office Life,' The American Lawyer, September 2, 2021
•'How South Florida Law Firms Are Capitalizing on the Great Florida Migration,' Daily Business Review, June 29, 2021
•'Specialized and Out-of-State Law Firms Dominated Florida Lawyer Hiring in 2020,' Daily Business Review, June 24, 2021
•'Local Law Firms Are Split on Internal Vaccine Messaging,' The Legal Intelligencer, May 3, 2021
•'Back to the Office: From Now to Labor Day, Pa. Firm Leaders are Solidifying Their Plans,' The Legal Intelligencer, May 6, 2021
•'These Firms Steered Clear of Layoffs and Salary Cuts in 2020,' The American Lawyer,' March 19, 2021
•'Pandemic Be Damned, Year-End Collections Are Steady (So Far),' The Legal Intelligencer, December 22, 2020
•'Law Firm Leaders: Marshall Dennehey's G. Mark Thompson,' Law360, May 20, 2020

Thought Leadership

Media Commentary

G. Mark Thompson Quoted in The American Lawyer Article on Staffing in Defense Industry

August 15, 2024

Media Commentary

Marshall Dennehey President & CEO Featured on Cover of Best's Review

May 1, 2024

Marshall Dennehey President & CEO G. Mark Thompson was featured on the cover of the May 2024 issue of Best's Review and quoted in the article, 'For the Defense.'

News

Marshall Dennehey Earns “Best Places to Work” Honor for 14th Straight Year

May 19, 2026

Marshall Dennehey Named to BTI Associate Satisfaction A-Listers 2026

May 7, 2026