O'Haire made his World Championship Wrestling (WCW) debut on the June 26, 2000 episode of Nitro, as he and Mark Jindrak defeated The Filthy Animals (Rey Mysterio and Juventud Guerrera).
On the July 3 episode of Nitro, O'Haire and Jindrak faced the Misfits in Action (General Hugh G. Rection and Corporal Cajun) to determine the number one contenders for the World Tag Team Championship, but were defeated. Despite this, O'Haire and Jindrak faced then-World Tag Team Champions KroniK and Vampiro and The Great Muta in a three-way match for the championship, but were unsuccessful in winning the titles. In August, O'Haire and Jindrak helped form The Natural Born Thrillers with Mike Sanders, Shawn Stasiak, Chuck Palumbo, Johnny "The Bull" Stamboli, and Reno. They were briefly mentored by Kevin Nash. In September, O'Haire and Jindrak won the World Tag Team Championship for the first time.
O'Haire and Jindrak won the titles once more before splitting when O'Haire and Jindrak participated in a tag team battle royal with their Natural Born Thrillers teammates Stasiak and Palumbo. After the conclusion of the match, Sanders declared both teams victorious and said that the teams should trade partners. As a result, O'Haire formed a new tag team with Palumbo, while the second team consisted of Jindrak and Stasiak.
Palumbo and O'Haire defeated The Insiders (Diamond Dallas Page and Nash) in January 2001. A short time later, The Natural Born Thrillers broke up when Stasiak and Jindrak became jealous of Palumbo and O'Haire's success. The teams met at SuperBrawl Revenge on February 18 for the tag team gold. Palumbo and O'Haire retained their titles. O'Haire and Palumbo next feuded with Totally Buffed (Buff Bagwell and Lex Luger) and defeated them at Greed on March 18 to retain the Tag Team Titles.
Over the following two weeks, O'Haire and Palumbo feuded with Team Canada (Lance Storm and Mike Awesome), defeating them on the final episode of Nitro on March 26. WCW was purchased by the World Wrestling Federation (WWF), and both O'Haire and Palumbo's contracts were picked up.
O'Haire and Palumbo made their WWF debuts on the June 28, 2001 episode of SmackDown! as part of The Alliance, attacking the Hardy Boyz. O'Haire and Palumbo started feuding with the Acolytes Protection Agency in the following weeks, which ended at WWF Invasion on July 22 when the APA defeated them. Subsequently, O'Haire and Palumbo defeated the Hardy Boyz on the August 2, 2001 edition of SmackDown!.
O'Haire and Palumbo next dropped the WCW Tag Team Titles to The Brothers of Destruction (The Undertaker and Kane) on the August 9 edition of SmackDown!, and lost their rematch for the championship in a steel cage match the following week on Raw. O'Haire and Palumbo's last televised match together was on the August 26 edition of Heat, defeating The Holly Cousins (Hardcore Holly and Crash Holly).
Palumbo was thrown out of The Alliance in late October and joined the WWF in November. O'Haire returned to WWE on the June 30, 2002 edition of Heat, defeating Justin Credible. He made a few more appearances on Heat, in dark matches and at house shows throughout the rest of 2002, facing off against and teaming with, among others, Doug Basham, Damaja, D'Lo Brown, Johnny Stamboli, Shelton Benjamin, Charlie Haas, Christopher Nowinski and Raven.
In January 2003, vignettes started to appear on WWE programming showing O'Haire in his new gimmick — a Devil's advocate character. He urged people to commit adultery, break the law, not pay taxes, and not go to church, among other things. He ended each vignette with the line "I'm not telling you anything you don't already know." In 2003, O'Haire returned to the main SmackDown! roster, telling various superstars to perform indecent acts which included persuading Spanky to streak through the arena and Dawn Marie to flash the audience.
O'Haire's persona included a long black trench coat he wore to the ring and his obsession with spiders, including fairly new tattoos with black flames on each wrist and a red spider web shooting out from the flames on his left wrist and a blue spider web on his right wrist. On the inside of his left forearm was a blue spider and on the inside of his right forearm was a red spider. His titantron video was also inside the body of a spider with a spiderweb in the background. He quickly came under the tutelage of legend Roddy Piper in April 2003. His new persona was soon abandoned, but he held victories over major stars Rikishi, Funaki, Mr. America (by count out), Chris Benoit, and Eddie Guerrero. WWE officially released Piper from his contract on June 26, 2003, right after O'Haire and Piper made their last appearance together on SmackDown!. In late November 2003, he was involved in an injury that kept him out of action for the next month or so. When he recovered in February, he was released on April 3, 2004.
On September 8, 2014, O'Haire passed away.