Dr. Tessier grew up in the suburbs of Syracuse, NY, and attended Cornell University as an undergraduate biochemistry major. He was awarded a US Navy Health Professions Scholarship to attend medical school at the State University of New York at Buffalo where he graduated summa cum laude. He completed his Internal Medicine internship and residency at the Naval Medical Center in Portsmouth, VA, followed by an additional year as the Chief of Residents and a staff appointment as an internist and associate program director. He was transferred to the National Naval Medical Center in Bethesda (now the Walter Reed National Military Medical Center) just prior to the events of September 11, 2001 and the anthrax bioterrorism attacks.

Dr. Tessier left active duty to complete his Infectious Diseases fellowship at the University of Virginia; during and after his fellowship he conducted research on the role of bacterial protein toxins in the pathogenesis of anthrax, a disease he became interested in due to his experiences in the Navy. He then accepted a faculty position at Virginia Commonwealth University as a transplant infectious diseases consultant. He became the medical director for transplant infectious diseases at VCU and was promoted to associate professor. Family circumstances resulted in a move to north Texas and a new job as the medical director of antimicrobial stewardship at the John Peter Smith Health Network in Fort Worth, TX.

Dr. Tessier enthusiastically pursued a faculty appointment at UT Southwestern and joined the infectious diseases division in the autumn of 2018. He brings with him expertise in transplant and general infectious diseases, antimicrobial stewardship, the pathogenesis of diseases associated with bacterial protein toxins, as well as a passion for teaching medical students, residents, and fellows.