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Mark Donnelly

tel. (713) 659-7200
fax (713) 659-7203

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White Collar Criminal Defense
Business Litigation

Real Estate Litigation

Whistleblower/Qui Tam Actions


Randolph-Macon College

South Texas College of Law

Mark Donnelly has spent his career in the courtroom and now represents clients in various federal, state, and regulatory matters. With over 100 jury trials under his belt, Mark not only is extremely comfortable in the courtroom, but also has the knowledge and experience to guide clients through all phases of representation.

Mark joined Parker Sanchez & Donnelly after a twelve-year career in the Department of Justice.  At the DOJ, Mark served as Senior Advisor to the United States Attorney for the Southern District of Texas, the most prolific office in the country. In that role, Mark either directly handled or supervised every manner of action brought by the federal prosecutor’s office. Mark has extensive experience investigating white collar cases, having run the Southern District’s fraud division for over two years. His white collar practice included FCPA investigations, Healthcare Fraud, joint SEC matters, large scale investor fraud, and cyber security matters. Mark had regular contact with high-level justice department leaders and often handled cases jointly with DOJ prosecutors in Washington, D.C. In one of his last projects with DOJ, Mark wrote the eLitigation policy for the Southern District and worked with judges and attorneys to implement best practices.


Prior to his DOJ career, Mark spent eight years as a prosecutor with the Harris County (Houston) District Attorney’s Office. There, Mark cut his teeth in the courtroom on matters ranging from driving while intoxicated to capital murder. He also spent time in the public integrity section where he led investigations into elected officials and others charged with violating the public trust. Mark is a proficient Spanish speaker and was designated as a bilingual assistance prosecutor. He left that office having achieved the rank of Chief Felony Prosecutor.

In 2023, the Texas House of Representatives turned to Mark to assist with the historic investigation and impeachment trial of the Texas Attorney General. Mark worked with a team of seasoned lawyers and investigators to bring to light abuse of office allegations that led to the trial in the Texas Senate. Examples of his work are shown below and here.


A native Houstonian, Mr. Donnelly is also a servant to his hometown community. He was president of a local youth sports association for 4 years and that organization honored him with a plaque of appreciation which adorns the entryway to the fields. He was a board member of his church and volunteered as a member of the Houston golf Association. Mark has lectured throughout the country on topics ranging from trends in white collar crimes to trial advocacy and training.


Direct Examination of Gregg Cox:

Direct Examination of Joe Brown:

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