After graduating with honors from the University of New Mexico School of Medicine in Albuquerque, Dr. Longo completed his residency in Radiation Oncology at UCLA. As chief resident, he received the American Cancer Society Clinical Fellowship Award in Oncology at UCLA and became Board-certified in 1986. He then served on the clinical faculty at Stanford, then on the academic faculty at University of New Mexico Cancer Center, and presently on the clinical faculty at UCLA since 1991. He has been involved in Oncology research projects. He has been director of Templeton Radiation Center since 1991. Dr. Longo also serves on the Governing Board at Twin Cities Community Hospital and is moderator of their monthly Oncology Conferences for the Medical Staff.

Dr. Longo practices at the Templeton Radiation Oncology Medical Center.