Psicosis debuted in 1991 and was trained by Rey Mysterio, Sr. Not long after his debut, he would begin his legendary feud with Rey Mysterio Jr..
His first North America exposure was in the form of the AAA/IWC When Worlds Collide Pay-Per-View on November 6, 1994. He competed in a six-man tag team match with Fuerza Guerrera and Madonna's Boyfriend against Rey Mysterio, Jr., Heavy Metal and Latin Lover, and won the contest after Fuerza Guerrera forced Heavy Metal to submit.
Psicosis would soon carry his feud with Rey Mysterio, Jr. over to the Philadelphia-based promotion, Extreme Championship Wrestling. Regardless of the critics telling ECW booker Paul Heyman that "Lucha Libre would not go over in the United States", Psicosis and Rey Mysterio, Jr. ended up putting on the best match on the card a total of three times in the Fall of 1995. The first match was won by Rey Mysterio, Jr., with Psicosis then defeating Mysterio in a 2-out-of-3 Falls Match not long after, and then Mysterio ended the feud (temporarily) by defeating Psicosis in a Mexican Death Match, despite the fact that Psicosis dominated the match the entire time and scored several pinfalls over Mysterio.
Psicosis debuted for World Championship Wrestling at Clash of the Champions on January 26, 1996 and lost to Konnan. Initially, Psicosis was managed by Sonny Onoo, but soon went without a manager and became a frequent tag-team partner of La Parka and Juventud Guerrera, as well as feuding with the likes of Dean Malenko, Rey Mysterio, Jr. and Billy Kidman. Psicosis was a big part of the Latino World Order, as he joined the stable (led by Eddie Guerrero) in October 1998. On April 19, 1999 Psicosis defeated Blitzkrieg, Juventud Guerrera and Rey Mysterio in a 4-way to win the WCW Cruiserweight Championship for the first time, only to lose it to Rey Mysterio not long after. Psicosis lost his mask twice: in Mexico he was defeated by Rey Mysterio Sr. on August 1999, and in WCW on September 27, 1999, after losing to Billy Kidman "Hair vs Mask" match. Psicosis would go on to win the WCW Cruiserweight Championship for the second time in October 1999, after defeating Lenny Lane, who had gotten WCW in trouble with GLAAD. Psicosis soon dropped the WCW Cruiserweight Championship to Disco Inferno.
In the beginning of 2000, Psicosis ended up as Juventud Guerrera's bodyguard, as Guerrera would start imitating former WWE Champion the Rock, while Psicosis would stand around with his arms folded and not say a word or do anything. Psicosis was eventually released and headed back to Extreme Championship Wrestling.
Psicosis returned to Extreme Championship Wrestling on July 16 at ECW's Heat Wave 2000 Pay-Per-View and competed in an impromptu 4-Way Dace against Yoshihiro Tajiri, Little Guido and Mikey Whipwreck. Psicosis was eliminated by Tajiri, and would end up competiting against Tajiri in a feud that many still talk about to this day. Psicosis didn't last very long in ECW and would go on to work mostly in Tijuana for the next several months.
He would work for the short-lived World Wrestling All-Stars (WWA) promotion based out of Australia in 2001. Facing Juventud Guerrera in a ladder match on the debut show in October and later Juventud and Eddie Guerrero in a three-way in 2002.
In November 2001 he began working for Consejo Mundial de Lucha Libre (CMLL), making his Arena Mexico debut in a match also featuring Rey Misterio, Jr.. Soon Damian 666 and Halloween were brought in and his time in CMLL was generally spent tagging with the two as La Familia de Tijuana. He would appear on and off through June 2003.
Psicosis was featured on the Pay-Per-View debut of TNA, but did not last long. Psicosis headed to Xtreme Pro Wrestling (XPW), where he was a part of the La Familia stable, along with Konnan, Juventud Guerrera, Damien 666 and Halloween. Psicosis engaged in a short-lived feud with Super Crazy once XPW relocated to Philadelphia, Pennsylvania, with Psicosis winning both matches at the New Alhambra (formerly ECW) Arena. Psicosis would go on to compete in matches against Chris Chetti, Sonny Siaki, Jerry Lynn and Juventud Guerrera.
In March 2005, just before agreeing to a contract with World Wrestling Entertainment, he returned to AAA and began a feud with Psicosis II over the rights to the Psicosis name.
He made his WWE debut on June 12, 2005 at the ECW One Night Stand Pay-Per-View. He entered the ring wearing his trademark mask, but removed it before his match against long-time rival Rey Mysterio Jr.. Mysterio defeated Psicosis with his (Mysterio) signature move, "The West Coast Pop". A few weeks later, Psicosis debuted on the SmackDown! brand as a member of the Mexicools, along with Juventud Guerrera and Super Crazy. Their trademark accessories were riding to the ring on their "Juan Deere" lawnmowers and wearing work clothes. Juventud Guerrera would soon be released from WWE, leaving Psicosis and Super Crazy to go after the World Tag Team championships. They would be unsuccessful every time.
On June 9, 2006 Psicosis abandoned Super Crazy, and they were in the process of developing a feud, until Super Crazy was suspended for elevated enzymes in his liver. As a result, Psicosis was removed from WWE television, as creative had nothing else planned for him. This would be his last televised match on SmackDown! on July 21, 2006. Crazy was later drafted to WWE's RAW brand in September 2006, while Psicosis remained off SmackDown programming. He was inevitably released from his contract in late 2006.
At the end of 2006, he accidentally shattered his nose in a match against Hijo del Misterio, and also got his head shaved. He was rushed to a nearby hospital to get his nose set following the match.
In February 2007, he returned to AAA but only appeared until the end of March and would spend the next several months working independents throughout Mexico until October 2008 when he would once again return to AAA only to leave again.
In February 2008, he would say in an interview that he hoped to return to CMLL but ended up back in AAA by May.
The newspaper story claims that Psicosis asked to borrow Ramirez's black Mitsubishi, promising to return it later that night. Ramirez refused, leading to Psicosis pulling a gun on him and taking the car anyway. Ramirez called the police who set up roadblocks around Rosarito. Psicosis hit several cars while in the chase including one that had a pregnant woman inside. After catching him, police found out that the gun he used earlier in the night was actually just a water gun. 
There's a different Psicosis II who began using the same name and look after this Psicosis left to Promo Azteca and WCW, as a result of AAA booker Antonio Peña claiming ownership to the Psicosis name and gimmick. Because of this, Psicosis took on the moniker Nicho el Millonario and returned briefly to AAA to feud with Psicosis II over the name.
- His name was misspelled (as "Psichosis") on the back cover of the ECW One Night Stand 2005 DVD.
- His name is often pronounced "Psychosis" (most notably in WCW and WWE), despite being spelled Psicosis; ECW is one of the few American Wrestling Promotions that have pronounced his name as it is spelled.
- Has wrestled Rey Misterio Jr. over 500 times, according to Joey Styles at ECW One Night Stand 2005.
- Shortest reigning WCW cruiserweight champion, with a reign that lasted less than an hour
- Enjoys computer programming in his free time.
- Favorite wrestlers growing up were the Dynamite Kid and his brother Fobia.
- Enjoys listening to Metallica, and used "Battery" as his theme song during his first run in ECW.
- Used "Cherub Rock" by Smashing Pumpkins as his theme song in 2000 during his appearances in ECW.
- Appeared in the independent documentary, 101 Reasons Not To Become A Professional Wrestler.
- Appeared at only one ECW pay-per-view, Heat Wave 2000, in a three-way dance against Yoshihiro Tajiri and Little Guido.
- Finishing and signature moves
- Psycho Guillotine (Diving Legdrop)
- Psycho Stunner
- Tag teams and stables
- Wrestlers trained
- Theme music
Championships and accomplishments
- APW Worldwide Internet Champion (1 time)
- Mexican National
- WCW World Cruiserweight Champion (2 time)