A graduate of Louisiana State University with a Bachelor of Science, Dr. Castillo received his medical degree from Universidad La Salle Medical School in Mexico City , Mexico . Continuing his education and postgraduate training, Dr. Castillo completed an Internship/Residency at St. Luke's Roosevelt Hospital in New York , New York where he was honored as Chief Resident in Internal Medicine and continued his Fellowship training at The New York Hospital-Cornell Medical Center, New York, New York and served as Chief Fellow in Hematology/Medical Oncology.

Following post graduate training, he was in practice at the Ochsner Clinic Foundation in New Orleans , Louisiana.

An active researcher and published author, Dr. Castillo is affiliated and has served as a Principal and Sub-investigator in many Cooperative Group Clinical Trials including the National Surgical Adjuvant Breast and Bowell Project (NSABP), Southwest Oncology Group (SWOG), North Central Cancer Treatment Group (NCCTG), and Radiation Treatment Oncology Group (RTOG). A distinguished professional, Dr. Castillo has also received many honors including “Top Doctors in New Orleans” recognized by the New Orleans Magazine and the Community of Caring Award from the Ochner Clinic Foundation.

In addition, he is a member of several professional societies such as the American College of Physicians, American Medical Association, American Society of Clinical Oncology, American Society of Hematology, and New York State Society of Internal Medicine. Board certified in Medical Oncology/Hematology and Internal Medicine, Dr. Castillo is in private practice with the Southwest Regional Cancer Center .