Dr. David O'Brien graduated from Texas A&M College of Veterinary Medicine in 1994 and became a mixed animal veterinarian on the border in Laredo, Texas. He and his wife, Lisa, joined the army in 1996. As a U.S. Army Veterinary Corps officer, he served at Ft. Bragg, Saudi Arabia, Bahrain, and lead a mobile veterinary surgical unit in Korea. In 2001, they settled on a farm in Seguin to breed Warmblood horses. In 2011, David and Lisa became parents when they adopted their son, David.

Dr. O'Brien joined VCA Henderson Pass Animal Hospital in 2011 and became Medical Director in 2016.