Colonel Terri R. Zimmermann graduated with a B.A. with Honors in Government from the University of Texas in 1989 and received her J.D. from Georgetown University Law Center in 1992. She has been a member of the United States Marine Corps Reserve since 1989.

During her active duty tour at Marine Corps Air Station El Toro, California, she was a trial counsel (prosecutor), review officer, and civil law officer.

As a Reservist, she has served as the Reserve Chief Defense Counsel of the Marine Corps; Reserve Chief Trial Counsel of the Marine Corps; military trial judge; and military appellate judge on the Navy-Marine Corps Court of Criminal Appeals.

In her civilian practice, Col Zimmermann is the managing member of Zimmermann & Zimmermann, PLLC in Conroe, Texas. She is board certified in Criminal Law and Criminal Appellate Law by the Texas Board of Legal Specialization, and is a Board Certified Criminal Trial Advocate, National Board of Trial Advocacy. She practices primarily criminal defense and military law at the trial and appellate levels in state, federal, and military courts nationwide.