Genaro Contreras made his professional wrestling debut in 1968, after training under renowned Mexican wrestling trainer Diablo Velazco, under the ring name "Ringo Mendoza", adopting a Native American persona complete with feathered headdress. Contreras would later be joined by his brothers who wrestled as Cachorro Mendoza and Indio Mendoza. Mendoza won his first wrestling championship on November 29, 1974 when he defeated Aníbal to win the Mexican National Middleweight Championship. Mendoza would go on to hold the title for 822 days, over two years, before losing the title to Perro Aguayo on February 28, 1977. During the 822 day reign Ringo Mendoza defended the title against opponents such as Tony Salazar and Perro Aguayo. On July 3, 1977 Mendoza got a measure of revenge for his title loss as he defeated Perro Aguayo to win the NWA World Middleweight Championship, capturing the top title in this middleweight division. Ringo Mendoza would become synonymous with the NWA Middleweight Title as he captured it five times between 1977 and 1981 defeating such wrestlers as El Faraón], Perro Aguayo, Tony Salazar and Sangre Chicana. On June 6, 1980 Mendoza defeated Satánico to win his second Mexican National Middleweight Championship, holding it for 182 days before dropping it to El Faraón. In the 1980s Ringo began teaming more regularly with his brother Cachorro Mendoza, defeating Satánico and Espectro, Jr. in a tournament final to win the vacant Mexican National Tag Team Championship. On January 15, 1983 Ringo Mendoza became a double champion as he defeated El Faraón to win the NWA World Light Heavyweight Championship. On July 28, 1983 Satánico won the NWA Light Heavyweight Title from Ringo Mendoza but quickly lost it back to Mendoza. The Mendozas held the tag team title for a full 1,029 days before losing to Sangre Chicana and Cien Caras on April 12, 1985. A month later Ringo Mendoza lost the NWA World Light Heavyweight title to MS-1 on February 13, 1985. On November 28, 1986 Ringo Mendoza teamed up with Rayo de Jalisco, Jr. and Kiss to defeat Los Brazos (El Brazo, Brazo de Oro and Brazo de Plata) to win the Mexican National Trios Championship. The team held the title for 275 days before being defeated by Hombre Bala, Jerry Estrada and Pirata Morgan on August 30, 1987. In the late 1980s Ringo Mendoza began working for the Universal Wrestling Association (UWA) where he defeated Gran Cochisse to win the UWA World Junior Light Heavyweight Championship on April 29, 1989. Over a year later, on June 29, 1990 he lost the UWA title to long-time rival Perro Aguayo. From the early 1990s on Ringo Mendoza began focusing part of his time on training wrestlers, mainly working with young wrestlers on Consejo Mundial de Lucha Libre (CMLL)'s roster. Mendoza' last wrestling related highlight came on March 7, 1999 when he defeated Emilio Charles, Jr. to win the CMLL World Middleweight Championship, making him one of a very few wrestler to have won the Mexican, NWA World and CMLL World Middleweight championship to date. Mendoza defended the championship on at least 10 occasions over the 742 days his reign lasted, defeating wrestlers such as Blue Panther, Scorpio, Jr., Rey Bucanero, Zumbido, Apolo Dantés, Black Warrior, Villaño III and Mano Negra before losing the title back to Emilio Charles on March 18, 2001. Since losing the title Mendoza has focused on training wrestlers at CMLL's Mexico City and Guadalajara, Jalisco based wrestling schools. After almost 41 years in the wrestling business it has been reported that Ringo Mendoza is looking to wrestle his final match some time in 2009, officially retiring from the ring.