Developmental territories (2003–2004)

Snisky had a tryout match with the World Wrestling Entertainment (WWE) the day after winning the WXW Championship on October 20, 2003, in Wilkes-Barre, Pennsylvania at a Raw taping. Snisky, wrestling as Gene Snitsky, was defeated by fellow WXW wrestler "Smooth" Tommy Suede. It was following this match that he was signed to a developmental deal and sent to Ohio Valley Wrestling (OVW). Snisky wrestled in OVW as "Mean" Gene Mondo (a name inspired by "Mean" Gene Okerlund), and was presented as the kayfabe brother of Mike Mondo.

Debut and Heat mainstay (2004–2006)

He made his WWE debut on the September 13, 2004, edition of Raw^[3] against Kane in a no-disqualification match. As Kane, a heel at the time, prepared to injure Snitsky, he was distracted by Lita, who was (kayfabe) pregnant with Kane's child. Snitsky used the distraction to hit Kane from behind with the chair, causing Kane to fall on Lita, and causing Lita to miscarry her unborn baby. When interviewed about the incident, he claimed "it wasn't my fault" (which became his catchphrase). This facilitated a face turn for Kane and quickly established Snitsky as a full-time heel wrestler.

Snitsky, who had debuted against Kane as an apparent jobber, said years later that he was originally only supposed to make a one-night appearance, then return for OVW for more training before being called back up to the main roster on a full-time basis. The angle with Kane and Lita had gone over so well that WWE made a last-minute decision to promote him to the main roster full-time and flew him in to Raw on the company's corporate jet.^[6]

He was then situated in a major feud with Kane, which led to a match at Taboo Tuesday. In this match, Snitsky used a steel chair and crushed Kane's larynx. WWE used this angle as an excuse for Kane's absence, when in reality he was going to film the WWE-produced movie See No Evil. This feud resumed at the New Year's Revolution pay-per-view, when Kane returned and defeated Snitsky.^[7] On the January 31 edition of Raw, Snitsky lost a steel cage match to Kane to end the feud.

At Survivor Series, Snitsky had an encounter with a character similar to his own, Heidenreich, in which they both exchanged their views on each other – "I like .. your poetry."; "I .. like what you do.. to babies." — while breathing hard, both their trademark ways of talking. Snitsky was then in the main event as part of Team Triple H and facing Team Orton. During the match he was busted open by Maven before being disqualified for attacking him with a steel chair. At the 2005 Royal Rumble, the two met up again as Snitsky secretly partnered with Heidenreich, planning to interfere in Heidenreich's casket match with The Undertaker. It was later revealed that Kane was hidden in the casket, who pounced on both Snitsky and Heidenreich.^[8] They continued their fight in the crowd, before letting the casket match continue. Later that night, Snitsky competed in the Royal Rumble match in which he eliminated Paul London, before being eliminated himself by Batista.

When his rivalry with Kane ended, Snitsky had a shot at the Intercontinental Championship, which then was held by Shelton Benjamin. Snitsky lost by disqualification after hitting Benjamin with a steel chair.^[9]

He was absent from WWE television between April and May 2005 due to a blood clot in his stomach. He returned to action on May 28, and reappeared on Raw on May 30, where he began in earnest his televised feud with house show opponent Chris Benoit.^[10] The feud concerned Benoit's appearance at ECW One Night Stand; Snitsky was a "hired gun" for Eric Bischoff's Raw volunteers, brought in to try to invade the pay-per-view and ruin the ECW reunion.^[11]

Snitsky was then used by Edge and Lita to attack Kane and by Eric Bischoff as punishment to anybody that he did not like. On July 11 episode of Raw, Edge informed Snitsky that he knew about his female foot fetish and offered Snitsky to "have a go with Lita's feet" if he'd help him in a match against Kane.^[12] His history with Lita was addressed when she thanked Snitsky for his actions nine months earlier, stating that she was better off for not having given birth to Kane's offspring and then gave him a kiss as payment.

On the July 18 episode of Raw, Snitsky faced WWE Champion John Cena in the Lumberjack match where Chris Jericho picked all heel lumberjacks to make the odds unfair for Cena.^[13]

After a few weeks mainly wrestling on Heat, Snitsky formed a tag team with an initially reluctant Tyson Tomko. In their first team match together, they squashed the tag team of Viscera and Val Venis. The pair had some success as a tag team, becoming the number one contenders for the World Tag Team Championship at one point. They lost their shot at Big Show and Kane, both of whom Snitsky had feuded with in the past, and broke up in April 2006 when Tomko left WWE.

Following that, Snitsky turned face and formed a tag team with Goldust, defeating various teams of wrestlers on Heat, which eventually earned them an unsuccessful title shot against Spirit Squad. The team broke up when Goldust was released from WWE.^[14]

Brand switches and departure (2007–2008)

Snitsky in 2008

In 2007, Snitsky's character underwent a drastic overhaul and was now portrayed as a psychotic madman with a grotesque appearance. To this effect, all of the hair on Snitsky's head and face was shaved off (including his eyebrows), his teeth were colored a dark yellow, and several red marks were placed on his face. On the February 6, 2007, edition of ECW on Sci Fi, a vignette introduced the newly changed Snitsky to the viewers and announced him coming to ECW. Later during the same show, Snitsky debuted and assaulted the ECW World Champion Bobby Lashley.^[15] This re-established him as a monstrous heel, similar to Kane's unmasked gimmick. Over the next several weeks, Snitsky would run into the ring after matches and attack various ECW superstars, including CM Punk,^[16] Hardcore Holly^[17] Balls Mahoney,^[18] and Matt Striker.^[18]

On April 3, 2007, Snitsky faced Holly in a match, which he won. After the match, Snitsky wedged Holly's arm in between two steel steps and repeatedly hit the steps with a steel chair, in storyline, breaking Holly's arm.^[19] Snitsky then began a short feud with Balls Mahoney.^[20] Then, he would begin another short feud with Rob Van Dam. During this feud, Snitsky would suffer his first ECW loss when he was defeated by Van Dam by disqualification.^[21]

On the June 11 edition of Raw, Snitsky was drafted from ECW back to Raw as part of the WWE Draft. Snitsky made his return to the brand on the July 9 edition of Raw, defeating Super Crazy.^[22]

Snitsky continued to go undefeated on Raw throughout the summer, having pinfall victories over various wrestlers including Super Crazy, Val Venis, Rory McAllister,^[23] and Robbie McAllister.^[24]

On August 20, Snitsky competed in his first one-on-one main-event match since losing to John Cena on Raw in 2005, once again against Cena, which he lost via disqualification when Randy Orton interfered.^[25] This was Snitsky's first loss since returning to the Raw brand. On the September 10 Raw, it was revealed that Snitsky was not Vince McMahon's illegitimate son. Snitsky returned on the October 8 Raw, defeating Val Venis, substituting for Santino Marella, who was feuding with Venis.^[26] On December 3, Snitsky was pinned by Jeff Hardy in an Intercontinental Championship match, his first pinfall loss in the year.^[27] Snitsky last appeared on WWE television on the November 24, 2008 Raw, losing an Intercontinental Championship tournament match to CM Punk.^[28] On December 11, 2008, at his request, Snitsky was released from his WWE contract.^[6] On November 6, 2023 Snitsky made a cameo appearance on Monday Night RAW backstage with Chelsea Green saying his famous line "It Wasn't My Fault"