The Firm

MARK THIESSEN, Founding Partner and Trial Attorney

Mark Thiessen

Mark Thiessen is a nationally recognized trial attorney known for his aggressive representation and unwavering commitment to his clients. With over 140 Not Guilty verdicts and thousands of cases won throughout his career, Mark has established himself as one of the most formidable attorneys working in Texas courtrooms today. In total, Mark has tried over 200 cases to a jury.  

His expertise and exceptional track record have earned him 14 consecutive years as a Texas Super Lawyer and multiple Top 100 Super Lawyers designations in both Houston and Texas. His leadership and influence in the community are evidenced through his service on the Board of Directors for the Texas Criminal Defense Lawyers Association (TCDLA); 50th President of the Harris County Criminal Lawyers Association (HCCLA); and past president of the national organization DUI Defense Lawyers Association. Mark is also a member of the Texas Trial Lawyers Association and Houston Trial Lawyers Association.

Honestly, if Mark can win trials with some horrible criminal law facts against monster District Attorney’s offices; you can trust him to fight big insurance giants and represent the injured.  It’s way easier to have a client the jury feels sorry for who was wrongfully injured, rather than one the jury may hate for allegedly committing a crime. 

A FORCE OF NATURE IN THE COURTROOM

Mark Thiessen is known for his powerful presence in the courtroom. His ability to command attention and articulate compelling arguments makes him a formidable opponent and a trusted advocate for his clients. When insurance companies see Mark's name on a case, they know they're in for a fight — and that's exactly why our clients hire him.

Mark has handled a wide spectrum of cases, from high-stakes personal injury claims to quadruple intoxication manslaughter. His ability to secure victories in the courtroom — whether those be maximum settlements, Not Guilty verdicts, or dismissals — makes him an essential ally for any Texan facing their toughest legal battles. Unlike attorneys who settle for whatever the insurance company offers, Mark rolls up his sleeves and prepares every case as if it's going to trial, because that’s how you get results.

UNMATCHED CREDENTIALS

Mark is the only attorney in America who is quadruple board certified in:

  • Criminal Law by the Texas Board of Legal Specialization
  • DUI Defense by the National College for DUI Defense as approved through the American Bar Association
  • DUI Law by the DUI Defense Lawyers Association
  • Board Certified Advocate in Criminal Trial Law by the NBTA Foundation

Mark has also earned the American Chemical Society-Chemistry and the Law's (ACS-CHAL) Forensic Lawyer-Scientist designation — the highest form of scientific recognition available for lawyers. This scientific expertise allows him to challenge faulty evidence and hold negligent parties accountable in ways other attorneys simply cannot.

Mark’s reputation as a fearless, famous Houston attorney extends beyond his presence in the courtroom. In his free time, he competes in Brazilian jiu-jitsu as a black belt for Brazil-021 School of Jiu Jitsu in Houston and also trains Muay Thai. Mark is an avid snow skier, tennis player and waterman.  But above all else, he loves going on adventures with his family.

WE FIGHT GIANTS

Mark founded We Fight Giants with a simple mission: to give everyday Texans access to the same aggressive, trial-tested representation that big corporation law firms have…but now, against them. Insurance companies have armies of lawyers working to minimize your claim. With Thiessen Law Firm and Mark Thiessen in your corner, you have a fighter who has spent his career taking on powerful opponents — and winning.

HONORS AND ASSOCIATIONS

  • Texas Super Lawyer (14 consecutive years, 2013–2026)
  • Top 100 Super Lawyers in Houston (10 times)
  • Top 100 Super Lawyers in Texas (7 times)
  • Board Certified in Criminal Law by the Texas Board of Legal Specialization
  • Board Certified in DUI Defense by the National College for DUI Defense
  • Board Certified in DUI Law by the DUI Defense Lawyers Association
  • Board Certified Advocate in Criminal Trial Law by the NBTA Foundation
  • ACS-CHAL Forensic Lawyer-Scientist
  • AVVO 10/10 Superb Rating
  • AV Preeminent Rated
  • 50th President, Harris County Criminal Lawyers Association (HCCLA)
  • Board of Directors, Texas Criminal Defense Lawyers Association (TCDLA)
  • Charter Member, Past-President & Director, DUI Defense Lawyers Association (DUIDLA)

PROFESSIONAL EXPERIENCE

  • Thiessen Law Firm & We Fight Giants, Founder & Lead Trial Attorney
  • Trichter & Murphy, P.C., Associate Attorney
  • Brown Sims, P.C., Associate Attorney
  • Bell, Ryniker & Letourneau, Associate Attorney

EDUCATION

  • South Texas College of Law, Doctor of Jurisprudence
    • International Criminal Law studies at the University of Malta
    • BPP Law School, London, England
    • University of Hawaii
  • Texas Christian University, Bachelor of Business Administration in Marketing
    • Phi Delta Theta
    • Dean's List

 

Why choose Thiessen Law Firm?

Selecting the right attorney could be the most important decision you’ll ever make. At Thiessen Law Firm, we’ve built our reputation on fearless advocacy, strategic expertise, and unwavering commitment to our clients’ futures.  When prosecutors see our name on your case, they know they’re in for a fight.

Insider expertise

Insurance companies have an army of attorneys working to minimize what they pay you. Our team spent years on their side, learning exactly how they operate — and now they use that knowledge against them. When you hire Thiessen Law Firm, you get someone who knows their playbook, their tactics, and their pressure points.

Integrity

Insurance companies hide behind fine print and legal jargon. We don't. At Thiessen Law Firm, you'll always know exactly where your case stands, what your options are, and what we're doing to fight for you. Our reputation is built on transparency, honesty, and doing what's right for our clients, even when it's the harder path.

Tenacity

Insurance giants count on you giving up. They delay, they deny, and they hope you'll settle for scraps. But Thiessen Law Firm doesn't back down. We've built our name by outworking and outlasting the opposition. Whether it takes months of negotiation or putting them on trial, we fight until you get every dollar you deserve.

Results

Talk is cheap — results are what matter. We've secured millions for our clients when other firms said their cases were unwinnable. From multi-million dollar settlements to courtroom victories against corporate giants, our track record proves we don't just talk a big game — we fight and win.

1/4

We beat the giants — here's proof

When your future is at stake, results matter. At Thiessen Law Firm, our track record speaks for itself. We've successfully represented countless clients in desperate circumstances, turning impossible situations into victories. These case results represent real people whose lives were on the line — people just like you who trusted us to fight for their families. 

Here's a glimpse of what we've accomplished for our clients:

See Our Victories

$2.1 Million settlement

Auto Accident

Due to confidentiality requirements, the details of this case cannot be disclosed. The matter was resolved through a confidential settlement.

$2.4 Million settlement

Ride Share Sexual Assault

Due to confidentiality requirements, the details of this case cannot be disclosed. The matter was resolved through a confidential settlement.

$13.5 Million settlement

Commercial Car Accident

Due to confidentiality requirements, the details of this case cannot be disclosed. The matter was resolved through a confidential settlement.

Schedule a consultation

When you’re up against Goliath, you need attorneys who won't back down. Take the first step toward getting what you deserve; ask Thiessen Law Firm to fight for you by filling out the form below.

Loading contact form...

MessageCall