Rivera was hired by WABC-TV in 1970 as a reporter for "Eyewitness News". In 1972, he garnered national attention and won a Peabody Award for his report on the neglect and abuse of patients with intellectual disabilities at Staten Island's Willowbrook State School, and he began to appear on ABC national programs such as "20/20" and "Nightline" upon their launches in 1978 and 1979 respectively. After John Lennon watched Rivera's report on the patients at Willowbrook, he and Rivera put on a benefit concert called "One to One" on August 30, 1972, at Madison Square Garden in New York City (which Yoko Ono released posthumously in 1986, as "Live in New York City").