In addition to English, he speaks Spanish. Dr. Castillo is affiliated with California Pacific Medical Center (CPMC), Lucile Packard Children's Hospital Stanford, and Santa Clara Valley Medical Center (SCVMC). He graduated from the University of California, San Diego (UCSD), School of Medicine. For his professional training, Dr. Castillo completed residency programs at Stanford Hospital & Clinics and a hospital affiliated with the University of California, San Francisco (UCSF). He is in-network for Anthem, Blue Cross/Blue Shield, and Valley Health Plan, as well as other insurance carriers.