Gutierrez ya fara zama a Mexico a ranar 30 ga Afrilu, 1989, lokacin da yake dan shekara 14. An horar da shi daga kawunsa Rey Misterio Sr. kuma ya yi kokawa da wuri a Mexico inda ya koyi salon Lucha Libre wanda ya zama alamar kasuwancinsa. Yana da sunayen zobe kamar "La Lagartija Verde (The Green Lizard) " da "Colibrí (Humming bird) " kafin kawunsa ya ba shi sunan Rey Misterio Jr. A cikin 1991, an ba Mysterio "Mafi Kyawun Wrestler" a Mexico yayin kokawa a matsayin Colibrí. Tambaya: Shekaru nawa ne Mister Rey Misterio Jr. lokacin da ya fara kokawa da Lucha Libre?
yana da shekara 14 da haihuwa