People
Rex Mann is a trial lawyer who focuses his practice on patent litigation and other complex commercial litigation matters. Although his patent litigation practice is nationwide, he has extensive experience specifically in patent-heavy districts, including the Eastern and Western Districts of Texas. On commercial matters he often represents technology companies or works on matters involving complex technology, and his background in engineering enables him to deeply understand clients’ technologies and businesses to help them better achieve their goals. Rex’s work continues to garner him honors from legal publications such as The Best Lawyers in America®, IAM Patent 1000, Lawdragon, and Benchmark Litigation.
Rex’s intellectual property practice primarily consists of complex patent and trade secret litigation. He has handled bet-the-company patent and trade secret matters, including taking them to trial, and winning. Outside of litigation, he advises his clients on technology licensing issues, policies relating to intellectual property, and targeted patent prosecution advice relating to licensing and litigation.
“Rex’s patent litigation practice is heavily concentrated on matters arising in the Eastern and Western Districts of Texas. In fact, he began his legal career as a law clerk for the Honorable T. John Ward in the Eastern District of Texas, where he gained significant experience in federal trial practice and patent litigation, given the district’s intense patent trial docket.
Rex has significant trial experience and has tried more than 20 cases or arbitrations as first chair or in an otherwise stand-up role, and he has experience in all phases of trial. In addition to his civil trial work, Rex spent three months on loan as an assistant district attorney in Dallas County, where he tried numerous criminal jury trials to verdict and obtained a guilty verdict in each one.
Rex’s commercial litigation practice has included a wide variety of matters, including breach of contract, business torts, consumer class actions, RICO violations, securities laws violations, whistleblower or False Claims Act litigation, employment, fraud, suits against the government or government officials, and other related disputes. Given his background in engineering, the work Rex does for his commercial clients often involves technology issues. Moreover, his undergraduate and graduate degrees in civil and environmental engineering are helpful when working on matters in the environmental and oil and gas industries.
J.D., The University of Texas School of Law, high honors
M.S., Texas A&M University
B.S., Texas A&M University, cum laude
Texas
Law Clerk, Honorable T. John Ward, U.S. District Court for the Eastern District of Texas
Board Member, Dallas Association of Young Lawyers, 2017–2018
Board of Trustees, Dallas Children’s Advocacy Center, 2016–2022
Co-Chair of the Business and Career Development Committee, Dallas Association of Young Lawyers, 2015–2016
Co-Chair of the Judiciary Committee, Dallas Association of Young Lawyers, 2015–2017
District 6 Grievance Committee Member, State Bar of Texas, 2015–2018
February 3, 2026
King & Spalding Welcomes Nine-Partner Litigation Group in Expansion of Commercial and IP Litigation Capabilities
Patent, Trade Secret, and Other Intellectual Property Litigation
Halliburton v. U.S. Well Services (W.D. Tex.) As trial counsel, prevailed for U.S. Well Services in the trial of the first of three patent infringement litigations filed by competitor Halliburton, which claimed that U.S. Well Services infringed certain patents involving use of hydraulic fracturing software, as well as methods related to the operation and powering of U.S. Well Services’ fracturing sites—a win that Am Law recognized with a “Litigator of the Week” first-runner-up nod. Rex conducted key cross-examinations of Halliburton’s technical experts.
In the Matter of Certain Integrated Circuits, Components Thereof, and Products Containing the Same (ITC) Served as trial counsel to defend Advanced Micro Devices, Inc. (AMD) in a massive ITC action brought against AMD by its competitor Realtek Semiconductor Corp. Realtek accused AMD of infringing three patents relating to integrated circuit designs. AMD faced an exclusion order and a cease-and-desist order at the ITC. Administrative Law Judge (ALJ) Cameron Elliot’s decision found that all asserted claims of two of the patents were invalid for multiple reasons. For the third patent, he ruled that all asserted claims were not infringed by AMD, and that all but one of those claims were also invalid. Rex conducted multiple cross-examinations and direct examinations of expert witnesses and fact witnesses in the five-day trial.
See more
February 3, 2026
King & Spalding Welcomes Nine-Partner Litigation Group in Expansion of Commercial and IP Litigation Capabilities
Patent, Trade Secret, and Other Intellectual Property Litigation
Halliburton v. U.S. Well Services (W.D. Tex.) As trial counsel, prevailed for U.S. Well Services in the trial of the first of three patent infringement litigations filed by competitor Halliburton, which claimed that U.S. Well Services infringed certain patents involving use of hydraulic fracturing software, as well as methods related to the operation and powering of U.S. Well Services’ fracturing sites—a win that Am Law recognized with a “Litigator of the Week” first-runner-up nod. Rex conducted key cross-examinations of Halliburton’s technical experts.
In the Matter of Certain Integrated Circuits, Components Thereof, and Products Containing the Same (ITC) Served as trial counsel to defend Advanced Micro Devices, Inc. (AMD) in a massive ITC action brought against AMD by its competitor Realtek Semiconductor Corp. Realtek accused AMD of infringing three patents relating to integrated circuit designs. AMD faced an exclusion order and a cease-and-desist order at the ITC. Administrative Law Judge (ALJ) Cameron Elliot’s decision found that all asserted claims of two of the patents were invalid for multiple reasons. For the third patent, he ruled that all asserted claims were not infringed by AMD, and that all but one of those claims were also invalid. Rex conducted multiple cross-examinations and direct examinations of expert witnesses and fact witnesses in the five-day trial.
See more
February 3, 2026
King & Spalding Welcomes Nine-Partner Litigation Group in Expansion of Commercial and IP Litigation Capabilities
J.D., The University of Texas School of Law, high honors
M.S., Texas A&M University
B.S., Texas A&M University, cum laude
Texas
Law Clerk, Honorable T. John Ward, U.S. District Court for the Eastern District of Texas
Board Member, Dallas Association of Young Lawyers, 2017–2018
Board of Trustees, Dallas Children’s Advocacy Center, 2016–2022
Co-Chair of the Business and Career Development Committee, Dallas Association of Young Lawyers, 2015–2016
Co-Chair of the Judiciary Committee, Dallas Association of Young Lawyers, 2015–2017
District 6 Grievance Committee Member, State Bar of Texas, 2015–2018