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Marshall DenneheyShareholder, CEO, Executive Committee Member
G. Mark Thompson
Pro

G. Mark Thompson

5.0
9 reviews

2000 Market Street, Suite 2300, Philadelphia, PA 19103

Product Liability, General Liability, Fraud/Special Investigation and 2 more

About 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

Year joined

2001

Thought Leadership

Marshall Dennehey Named a 2026 'Best Law Firm' In Multiple Practice Areas by Best Lawyers

November 10, 2025
Marshall Dennehey has been named a '2026 Best Law Firm' in multiple practice areas, both nationally and across numerous regions of the country, by Best Lawyers .

Liberty Mutual Insurance Names Marshall Dennehey External Law Firm Partner of the Year

October 24, 2025
Marshall Dennehey is honored to accept the External Law Firm Partner of the Year Award from Liberty Mutual Insurance.

Marshall Dennehey Again Named to BTI Consulting’s Client Service A-Team

August 6, 2025
Marshall Dennehey has once again been recognized as a leader in client service, earning a spot on BTI Consulting’s Client Service A-Team 2025, which honors law firms delivering the highest levels of service to corporate clients.

Marshall Dennehey Named an “Innovation Standout” In BTI Report

June 24, 2025
Marshall Dennehey has earned recognition as an “Innovation Standout” in the BTI Law Firm Innovation Icons 2025 report.

Marshall Dennehey Awarded Prestigious Litigation Department of the Year Honors for Professional Liability and Appellate Law at the 2025 Pennsylvania Legal Awards

Appellate Advocacy & Post-Trial Practice
Accountants’ Professional Liability
Lawyers' Professional Liability
Miscellaneous Professional Liability
Securities & Investments Professional Liability
Health Care Liability
Behavioral Health Risk & Liability
Birth & Catastrophic Injury Litigation
Electronic Medical Record & Audit Trail Litigation
Emergency Medical Services
Long-Term Care Liability
Telehealth & Telemedicine
June 13, 2025
Marshall Dennehey was awarded the prestigious Litigation Department of the Year awards for Professional Liability and Appellate Law at The Legal Intelligencer’s 2025 Pennsylvania Legal Awards, held June 12 in Philadelphia.

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

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

 

G. Mark Thompson (Philadelphia, Pennsylvania) View website

Awards

AV Preeminent Peer Rated
This elite award is granted to attorneys who have been recognized by their peers for their very high ethical standards, with an average peer review score of 4.5 or higher.
Martindale-Hubbell Peer AV

Client Champion Awards

Client Champion awards recognize those attorneys who excel at service as affirmed by their clients. The awards, based on the quantity and quality of an attorney’s Martindale-Hubbell client reviews, demonstrate an ongoing commitment to delivering excellent client service. Award recipients stand out from their peers with a platinum, gold or silver icon.

Champion Badge Silver

At least three reviews and a score of 4.0 or higher.

Champion Badge Gold

At least six reviews and a score of 4.2 or higher.

Champion Badge Platinum

At least ten reviews and a score of 4.5 or higher.

Martindale Peer Awards

A lawyer who receives a minimum threshold of qualifying responses from fellow attorneys can qualify for one of three prestigious Martindale-Hubbell Peer Review Ratings:

Martindale-Hubbell Peer AV Preeminent Rating

AV Preeminent®: The highest peer rating standard. This rating signifies a large number of the lawyer’s peers rank him or her at the highest level of professional excellence for their legal knowledge, communication skills and ethical standards.

G. Mark Thompson got this award in 2021

Martindale-Hubbell Peer Distinguished Rating

Distinguished: An excellent rating for a lawyer with some experience. This rating indicates the attorney is widely respected by their peers for high professional achievement and ethical standards.

Martindale-Hubbell Peer Notable Rating

Notable: This rating indicates that the lawyer has been recognized by a large number of their peers for strong ethical standards.

Avvo Awards

Avvo Top Contributor

Avvo Top Contributor: The Avvo Top Contributor Award is granted to attorneys who have earned significant contribution points in a given year on our sister site, Avvo.com. Contribution points are earned by answering questions in Q&A, publishing Legal Guides, and other useful contributions to the Avvo community.

Avvo Client Choice

Avvo Client’s Choice: The Avvo Client's Choice Award Badge is granted to attorneys with a significant number of 4+ star reviews in a given year.

Reviews for G. Mark

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Overall Rating
5.0
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5.0
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9
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Services

Areas of Law

  • Insurance Defense
  • Other 4
    • Product Liability
    • General Liability
    • Fraud/Special Investigation
    • Hospitality and Liquor Liability

Practice Details

  • Firm Information
    Position
    Shareholder, CEO, Executive Committee Member
    Firm Name
    Marshall Dennehey
  • Representative Cases & Transactions
    Cases
    Significant Representative Matters: Defended a corporation
    obtained summary judgments in multiple federal lawsuits alleging sponsorship, production, distribution
    sale of videos depicting plaintiffs' underage participation in various spring break contests.
    Defended a manufacturer
    obtained satisfactory confidential resolution of claims brought by 51 factory employees alleging toxic exposure.
    Defended a state agency
    obtained defense verdict in wrongful death trial alleging inadequate traffic control.
    Defended a major insurer
    obtained defense verdict in trial brought by owner of an oddities museum whose collection
    building was completely destroyed by fire.
    Defended a tourist destination
    obtained summary judgment in a negligence action brought by a contracted performer rendered quadriplegic as a result of an accident during a gymnastic slam dunk exhibition.
    Defended a company
    obtained defense verdict on appeal in lawsuit alleging bottle exploded while being h
    led by plaintiff.
    Defended a tourist destination
    obtained defense verdict in trial alleging inadequate slip resistance of drainage grates.
    Defended
    settled numerous lawsuits involving tractor trailer rollovers allegedly caused by improper loading of cargo.
    For nearly 20 years, defended theme parks
    tourist destinations throughout Florida in hundreds of cases involving amusement rides, wild animals, negligent security, E-coli outbreaks, slip
    falls, defamation, food poisoning, false imprisonment
    matters of intellectual property.
    Representative Cases: Anheuser-Busch, Inc. v. Lenz, 669 So. 2d 271 (Fla. 5th DCA 1996)
    Becton v. Metal Container Corp., 856 So.2d 982 (Fla. 1st DCA 2003)
    Jordan v. Sea World of Florida, Inc., 938 So.2d 991 (Fla. 5th DCA 2006)
    Badillo v. Anheuser-Busch, 19 Fla. L. Weekly Fed. D 641 (M.D. Fla. 2006)
    Published Works: Experience is the Best Teacher for Lateral Moves, The Legal Intelligencer, Top Laterals Supplement, February 24, 2015
    Protective Orders: Sword
    Shield in the War of Discovery, 12: 3 The American Journal of Trial Advocacy, Summer 1989
  • Additional Links
    http://www.marshalldennehey.com/attorneys/g-mark-thompson

Experience

  • Bar Admission & Memberships
    Admissions
    1989, Florida
    1990, U.S. District Court Middle District of Florida
    1998, U.S. Court of Appeals 11th Circuit
    2012, Pennsylvania
    Supreme Court of the United States
    Memberships

    Associations & Memberships

    Claims & Litigation Management Alliance (CLM)
    Defense Research Institute
    International Amusement & Leisure Defense Association
    International Association of Amusement Parks and Attractions (IAAPA)
    Orange County Bar Association

  • Education & Certifications
    Law School
    Cumberland School of Law, Samford University, Birmingham, Alabama
    Class of 1989
    J.D.
    Dean's List, The American Journal of Trial Advocacy, Member, 1987-1989
    Other Education
    University of Florida
    Class of 1984
    B.A.
    Presidential Recognition for Outstanding Contribution to the University

Contact G. Mark Thompson

Shareholder, CEO, Executive Committee Member at Marshall Dennehey
5.0
9 reviews

2000 Market Street, Suite 2300Philadelphia, PA 19103U.S.A.

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Fax: (407) 839-3008

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Attorneys FAQs

  • What year was this attorney first admitted to the bar?
    G. Mark Thompson was admitted in 1989 to the State of Florida.
  • Is this attorney admitted to the bar in more than one state?
    Yes, G. Mark Thompson is admitted to practice in Florida and Pennsylvania.
  • Is this attorney admitted to practice in any U.S. Federal Courts?
    G. Mark Thompson is admitted to practice before the United States Court of Appeals for the Eleventh Circuit, United States District Court for the Middle District of Florida and United States Supreme Court.
  • Is this attorney Martindale-Hubbell Peer Review rated?
    Yes, G. Mark Thompson has a 5.0 Peer Rating from Martindale-Hubbell.
  • What law school did this attorney attend?
    G. Mark Thompson attended Cumberland School of Law, Samford University, Birmingham, Alabama.

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