He is in-network for Blue Cross/Blue Shield, Blue Cross Blue Shield Bronze, and Blue Cross Blue Shield Gold, in addition to other insurance carriers. Dr. Greenwell attended medical school at the University of Texas Medical Branch School of Medicine. For his residency, Dr. Greenwell trained at a hospital affiliated with the University of Texas Medical Branch at Galveston. He has received the following distinction: Texas Super Doctors. He is affiliated with Seton Highland Lakes Hospital, Seton Medical Center Austin, and Seton Medical Center Williamson.