Greg Marks


Practice Areas

Greg Marks has dedicated the last 20 years to helping victims who have suffered serious, catastrophic injuries. He understands the emotional, financial, and physical pain caused by an unexpected accident and takes care to guide his clients through this trying time. He has built his reputation through providing compassionate, personal service and creative, expert legal representation.


Greg has dedicated his law practice to helping victims who have been injured as a result of negligence, defective, and dangerous products and by the conscious disregard of safety products. He is Board Certified in Personal Injury Trial Law by the Texas Board for Legal Specialization and has done extensive legal work in exposing vehicle and product defects and enacting changes that ultimately save lives. As a family man, he understands the challenges his clients may be facing and is committed to guiding them every step of the way. He takes great pride in his personal service and is dedicated to a client-focused approach to the law.

Greg is a Past President of the Dallas Trial Lawyers Association and currently serves on the Board of the Texas Trial Lawyers Association (TTLA). He is a member of the American Board of Trial Advocates and is an AV®-rated attorney (Martindale-Hubbell Peer Review Ratings). He has been repeatedly been named to Best Lawyers and Super Lawyers and was named “Lawyer of the Year” in Plaintiff’s Product Liability in 2020 by Best Lawyers. He is a member of the Million Dollar Advocates’ Forum, the Dallas Bar Association, the TTLA, and the American Bar Association. He has been admitted to practice law before all state and federal courts in Texas, the Northern District of Indiana, the Western District of Louisiana, the Southern District of New York and the United States Judicial Panel on Multidistrict Litigation.

Prior to practicing law, Greg served as a civil engineer for an offshore drilling company. After changing career paths and graduating in the top 15% of his class in law school, he held a position with a prestigious Dallas law firm, representing corporate clients and businesses. Through this early experience, Greg developed his talent for preparing and trying complex lawsuits and jury trials. While it was a lucrative position, he wanted to use his talents and experience to help individuals and make a positive impact on their lives. So, for more than two decades, he has followed his passion of helping individuals by serving as a personal injury lawyer and fighting for victims of car accidents, vehicle defects, truck accidents, construction accidents, wrongful death, and other catastrophic accidents. In 2011, Greg joined with his longtime friend and colleague, Mike Guajardo, to form Guajardo & Marks, L.L.P. In 2021, Guajardo & Marks merged with Slack Davis Sanger.


  • B.S. in Civil Engineering, Texas A&M University
  • J.D. (with honors), Dedman School of Law at SMU

Professional Associations

  • Dallas Trial Lawyers Association, Past President
  • Texas Trial Lawyers Association, Board of Directors
  • American Board of Trial Advocates
  • Million Dollar Advocates’ Forum
  • State Bar of Texas
  • Dallas Bar Association
  • American Bar Association

Honors & Awards

  • Board Certified, Texas Board of Legal Specialization, Personal Injury Trial Law
  • The Best Lawyers in America
    • Lawyer of the Year, Plaintiff’s Product Liability, 2020
  • AV Preeminent Rated by Martindale-Hubbell
  • Super Lawyers, 2007-present



Rangel v. P.A.M. Transport (2017)

A busy interstate highway crowded with 18-wheelers can be a recipe for tragedy, as it was for Jose Rangel and his family from Laredo, Texas, two days before Christmas in 2013. Rangel, his wife Martha, and their daughter were traveling from Laredo to San Antonio when the acts of two negligent trucks drivers changed their…

Case Details