Perro Aguayo Jr. was the son of Mexican wrestling legend Perro Aguayo, who helped found the promotion AAA in 1992. Aguayo Jr. debuted in the ring at just 15 years old in 1995, and frequently teamed with his father. In his debut, he defeated Juventud Guerrera in an “Olympic Rules” match at TripleMania III-B. Aguayo Jr. and his father won the Mexican National Tag Team Championship twice. In 1995, Aguayo Jr. worked his first major show in June, when he lost to Guerrera at TripleMania. He created his first stable with three other young luchadors known as Los Junior Atómico. After taking multiple losses, the group disbanded and Aguayo Jr. began to team with Místico, the original Sin Cara in WWE, with whom he won the Mexican National Tag Team Championship.

Aguayo Jr. competed in AAA for eight years, then headed to CMLL in summer 2003, initially as a face to team with Negro Casas. Having often competed as a heel, Aguayo Jr. didn’t exactly win the crowd’s adoration, so the company turned him back to the darkside, a switch that would occur several times. His father also often made appearances throughout his time with CMLL, including during Aguayo Jr.’s feuds with Universo 2000 and El Hijo del Santo. His final feud with CMLL, in his first run, was against Héctor Garza, which ended in a hair-versus-hair match that saw Aguayo Jr. win with a low blow.

Aguayo started his own stable during his time in CMLL known as Perros del Mal. Over the years, the stable featured former WCW stars such as Damian 666, Halloween, and Hector Garza, and current AEW stars Penta El Zero Miedo and Taya Valkyrie. Perros del Mal, or “The Dogs of Evil,” had a motto of “Dios perdona, los Perros no” (“God forgives, the Dogs don’t.”).