Dr. Flenniken grew up in Colorado and went to undergraduate and veterinary school at Colorado State University. After graduation in 1996, he spent 2 years working as a mixed-animal practitioner in Cortez, Colorado. Dr. Flenniken has been with VCA North Academy Veterinary and VCA Briargate Veterinary Clinics since 1998.

He and his wife, Lana, have one son, two cats and a snake. Current activities are trail running and obstacle course racing.