On September 1977, he was named chief of pediatric services of Malcolm Grow Medical Center and on March 1980, was named chairman of the Department of Pediatrics. On June 15 of that same year, he was promoted to lieutenant colonel. He served at Malcolm Grow until July 1983, when he was transferred to the U.S. Air Force Regional Hospital, MacDill Air Force Base, Florida as chief of hospital services. On September 20, 1984, Rivera was promoted to colonel, and in November 1984 he was named commander of the 56th Medical Group.