Fitzgerald is a veterinarian at Alameda East Veterinary Hospital, where the Animal Planet television series "Emergency Vets" and its follow-up "E-Vet Interns" were filmed. For the past 25 years, he has been an assistant professor adjunct at the University of Denver, where he teaches a course called "Perspectives in Veterinary Medicine". He also serves as a veterinary consultant for the Aurora, Colorado police department's K-9 division. He has written chapters in medical texts on subjects such as emergency veterinarian medicine, toxicology, and reptile medicine and surgery.