Mysterio is the nephew of Rey Misterio Sr., He began his professional wrestling career in 1989 on the independent circuit. He was 14 years old. He signed with Asistencia Asesoría y Administración (AAA) in 1992. After a short time wrestling for Extreme Championship Wrestling (ECW), Mysterio went to work for World Championship Wrestling (WCW) in 1996. In WCW, Mysterio helped popularize "lucha libre" in the United States. This led to cruiserweight wrestling divisions being more popular. He won the WCW Cruiserweight Championship five times and the WCW World Tag Team Championship three times. He then wrestled for Consejo Mundial de Lucha Libre (CMLL). Mysterio joined World Wrestling Entertainment (WWE) in 2002.