Due to having extended family in Colorado, Dr. Gary Tateyama chose Colorado State University, located in Fort Collins, Colorado, as his choice for his college studies where he earned his Bachelor of Science in Microbiology in 1992 and his Doctorate of Veterinary Medicine in 1996. In 1990, during vacation breaks from college, he started working for Dr. Steve Dunbar (original owner of East Hills/Eastlake Animal hospitals that became VCA Yorba Regional Animal hospital) as a kennel attendant and technician. Right after graduating from vet school, Dr. Tateyama signed on to help Dr. Dunbar convert East Hills Animal Hospital into a 24 hour emergency hospital where he served as the primary emergency veterinarian for 10 years. In 2006, one year after the opening of Yorba Regional Animal Hospital and 10 years after graduation and starting emergency work, Dr. Tateyama decided it was time to experience normal working hours and switched to being a general daytime practitioner where he has stayed ever since.

When not working, Dr. Tateyama loves to cheer on the Denver Broncos whom he loves dearly. He is also a fan of the Rockies, Angels, Lakers, and Nuggets. In between Denver Broncos and other sports' seasons, Dr. Tateyama likes to hang out on the golf course, go to movies, amusement parks, and travel. In 2015, Dr. Tateyama took on the sport of Spartan racing and so multiple times a year he will be running trails and conquering obstacles all over. He also enjoys spending time with his husband, Kyle, and their pit bull mix, Sedona, who they rescued from a Los Angeles shelter in 2022.