DWI & Criminal Law Specialist
Mark Thiessen prides himself on being an aggressive trial lawyer. If the district attorney will not bargain or justice will not be served by allowing the client to plead guilty, Mark passionately and professionally represents his clients at trial. He has won DWI cases from total refusals up to quadruple intoxication manslaughter. Mark has earned formidable reputation for being a tenacious Houston DWI trial lawyer, and he works hard to maintain that status. Mark is licensed and tries cases in Texas and Colorado.
Since opening Thiessen Law Firm, Mark has continued to add to his growing list of accomplishments. In addition to his widely publicized feats as a winning Houston intoxication manslaughter lawyer, Mark Thiessen was the youngest criminal Super Lawyer in Texas in 2013. As of 2023, Mark is a 12 time Texas Super Lawyer, 8 time Top 100 Super Lawyers in Houston and 5 time Top 100 Super Lawyers in all of Texas. For four years, Mark has been the only DWI lawyer listed in the Top 100 in Houston and the only DWI Specialist Super Lawyer listed in the Top 100 Lawyers in Texas.
Mark is the only lawyer in America who is 4x 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 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.
In addition to DWI, he has also expanded his firm’s leadership into additional practice areas, including:
- Houston BWI
- Houston drug lawyer
- Houston child custody
- Father’s rights in Houston, Texas
- Houston juvenile lawyer
- Aggravated assault lawyer in Houston
- Head injury attorney in Houston
Mark is also a frequent legal seminar lecturer, author of numerous published legal articles, and a faculty member for various organizations. Mark is an international lecturer and is regularly called on to speak and educate students, police officers, lawyers and judges.
Mark Thiessen was born and raised in Houston, Texas. Mark attended the Village School and St. Francis Episcopal Middle School before graduating from the Kinkaid School in 1996. Mr. Thiessen then attended and graduated from Texas Christian University in 2000 with a Bachelor’s of Business Administration in Marketing. While at TCU, Mark was a member of Phi Delta Theta fraternity and on the dean’s list.
Following his time at TCU, Mr. Thiessen returned to Houston and began his law school education at South Texas College of Law (STCL). Mark made the most of his time at STCL, actively taking part in mock trials and campus law societies. Mark’s passion for the law also took him abroad: he has studied at the International Criminal Law at the University of Malta, the BPP Law School in London, England, and at the University of Hawaii. Studying in these unique legal environments required Mark to adapt to various social, cultural, ethnic, and economic groups, which is evident in his approach and personality to this day.
After graduating from law school, Mark practiced civil law at Bell, Ryniker & Letourneau and at Brown Sims, P.C. In 2006, he followed his passion for criminal law by joining the team at Trichter & Murphy, P.C., where Mark was able to study under some of the foremost legal authorities in Texas. After five years with Trichter & Murphy, P.C., Mark decided to start his own law firm, thus opening Thiessen Law Firm.
Although his practice includes all areas of criminal defense, Mr. Thiessen specializes in cases regarding DWI, drugs, and controlled substances. The trial of a DWI case dictates that, on any given date, a trial lawyer must be not only well-versed in Rules of Evidence, case law pertaining to DWIs, and constitutional law, but also numerous areas of science such as anatomy, physiology, toxicology, chemistry, computer science, biology, and physics. Additionally, Mark has studied many hours of trial strategies in order to properly educate jurors and judges on the sciences involved.
Mark is the current DWI Committee co-chair and on the Board of Directors for the Texas Criminal Defense Lawyers Association (TCDLA), the 50th President and on the Board of Directors for Harris County Criminal Lawyers Association (HCCLA) and a Charter Member and Treasurer and Director for DUI Defense Lawyers Association (DUIDLA).
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.
If you have a case and want an attorney who does not back down, call Mr. Thiessen today: 713-864-9000.
