Mario Diaz

Attorney at Thomas J. Henry Law's San Antonio Office

Mr. Mario Diaz is a native of San Antonio, Texas. After graduating from Taft High School, he attended Our Lady of the Lake University as a Moye Scholarship recipient and earned a B.B.A. in Computer Information Systems and Security. After graduating summa cum laude, Mr. Diaz returned to Our Lady of the Lake and earned his M.B.A. in Management where he was inducted into the Delta Mu Delta International Honor Society.

Prior to law school, Mario worked in retail banking as a supervisor at different branches of a large credit union, helping individuals to achieve their financial goals. Mr. Diaz also worked as a mortgage processor for a large bank prior to and during law school, assisting borrowers with the home-buying process through closing.

Mr. Diaz attended St. Mary’s University School of Law as a Dean’s Scholarship recipient. During his time at St. Mary’s, he served as a board member of the Tarlton Inn chapter of Phi Delta Phi, an international legal honor society, and also had the opportunity to work as a research assistant for a professor. He also clerked for a boutique civil litigation firm as well as a mid-size personal injury firm during his law school career. While clerking, Mr. Diaz gained extensive legal experience, especially in litigation.

Mr. Diaz graduated cum laude, finishing in the top 10% of his St. Mary’s law class, and was inducted into the Harlan Society as a result. Mr. Diaz now strives to apply the skills and experience he has gained in his professional and academic careers as a lawyer representing his clients.

Mr. Diaz is a sports fanatic and is a San Antonio Spurs and New Orleans Saints fan. He enjoys spending time with his family, playing with his cats Oso and Bella, reading, watching movies, and cooking.



  • State Bar of Texas


  • St. Mary’s University School of Law, San Antonio, Texas (J.D.)
    • Dean’s Scholarship recipient
    • Linda and Dave Schlueter 2018 First-Year Moot Court Competition, quarter-finalist
    • Faculty Award for Academic Excellence, Texas Civil Procedure I-Section E
    • Lexis+ Proficiency Certified
  • Our Lady of the Lake University, San Antonio, Texas (M.B.A.)
  • Our Lady of the Lake University, San Antonio, Texas (B.B.A.)
    • Summa Cum Laude
    • Moye Scholarship recipient


Mr. Mario Diaz and our team of San Antonio injury attorneys are located at 5711 University Heights Blvd., Suite 101, San Antonio, Texas 78249. We provide free walk-in case consultations Monday – Friday, 8:00am – 6:00pm. To start a consultation over the phone or to speak with your attorney, call 210-874-2615.

See what our clients have to say about their experience working with their legal team in San Antonio:

Even though it was a long road I am glad I choose Thomas J. Henry as my lawyer to handle my case and seek justice with a drunk driver who could have take my life. All of the attorney’s were professional and very knowledgeable. — Tiffany Guitron

I found that my experience with Thomas J. Henry was nothing but excellent and positive. I literally was taken care of from the very beginning. I was involved in an accident in which left me with neck and spinal injuries in which I had no idea where to turn. Every one at the law firm helped me immensely and genuinely cared about me. i highly recommend this law firm to anyone who has been injured in an accident. — Julia Rojas Ramirez

TJH helped me after I was rear ended by a motorist on the freeway. They kept me informed of the legal process and made me feel confident that my needs were a priority. I would recommend their services to anyone in need of legal guidance. — Melinda Aguilar

Thomas J Henry did an outstanding job for me. Client care was never lacking, even if my attorney was out of office and I left a voicemail, I received a call back as soon as 30 minutes later. They have an unrivaled amount of dedication to their clients and a passion for their work. Through my experience with the law firm and everyone involved in my case, I would highly recommend anyone to use them. — Zach Aubin

Never got impatient with myself, my husband , or any of our children, but they always remain determined to not only win-but to get us justice for the wrongs done to us. The phone calls, emails, and extensive efforts all paid off. We will recommend and endorse this attorney for years to come. We love the attorney and paralegal that was assigned to our case and even too especially Mr. Henry. Thank you all for being such a great team! — Monica Castro

Do not wait! If you have been injured in an accident, call Thomas J. Henry Law. We have San Antonio car accident attorneys and San Antonio truck accident lawyers available 24/7, nights and weekends to assist you with your claim.

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