The son of legendary comic actor and producer Tommy Muniz and brother of Pedro Muņiz; who is also a comedian, producer and actor, Rafo began acting with his father as his father's son in the legendary sitcom Los Garcia (The Garcias) on Puerto Rico's Canal 7 (channel 7) during the late 1970s.
From there on, Rafo had on and off work as an actor, but by 1985, he became a game show host at WAPA-TV. By that era also, he established a company named Promotores Latinos, where he performs as company President and main show producer. In 1989, Promotores Latinos produced a Spanish version of MTV's show Remote Control, but they and WAPA-TV were sued for using the name and likeness of the show without any previous permission, so the show had to be called off quickly. Muņiz and his company had former Menudo member Xavier Serbia be the host of that show, named Control Remoto.
During the 1990s, Muņiz was one of the top producers in Puerto Rico, and his firm represented such artists as Olga Tanon, Aaron Carter, Ricardo Arjona and many others during some of their concerts in Puerto Rico. Tanon split from his company in 2002, and she and Muņiz have expressed negative views of each other publicly after the breakup. Muņiz, however, kept busy and quickly signed another Merengue singer, Melina León and TV personality, Silverio Perez, to be represented by him.