Nash has wrestled under various ring names for World Wrestling Entertainment, World Championship Wrestling, and Total Nonstop Action starting in 1990 with WCW, where he toiled in the undercard matches for a few years. He caught the eye of an injured Shawn Michaels, who inquired about bringing him into the WWF, which Nash achieved by asking for his release under the premise he was done with the wrestling business. Instead, he immediately signed with the WWF to wrestle as Diesel. One year later, Nash was the reigining WWF Intercontinental champion, shortly thereafter winning the WWF Tag Team championships with Michaels. After their team dissolved, Diesel won the WWF World Heavyweight championship, becoming the first man to hold the title for 300 consecutive days in over five years.
When Kevin Nash's WWF contract expired in June 1996, he opted to move to World Championship Wrestling with Scott Hall, where they founded the New World Order. Nash worked both as a wrestler and as a booker while in WCW, which ruffled a lot of feathers backstage within the locker room. Regardless, Nash won the WCW World Heavyweight championship on four separate occassions before the company was sold to the WWF in March 2001.After their WCW contracts through AOL-Time Warner expired, Kevin Nash, Scott Hall, and Hulk Hogan returned to the WWF as the New World Order (WWF signed Nash to a two-year contract on January 3, 2002, with an option for a third year). Unfortunately, nWo had run its course and it did not make any memorable impact within WWE. After Nash tore his quadriceps in July 2002, he sat out until shortly after WrestleMania XIX when he returned to challenge HHH. Nash also feuded with Chris Jericho before his last WWE match at SummerSlam 2003 after which he underwent corrective neck surgery.
Kevin Nash found a home with TNA in November 2004, coming in alongside Scott Hall to form "The Kings" with Jeff Jarrett. The Kings were short-lived, and most analysts expected the same fate of Nash/TNA as well, but Nash proved a lot of his critics wrong by continuing their working arrangement for about six years before he signed with WWE in January 2011, resurrecting his Diesel as a surprise entrant for that month's 40-man Royal Rumble.Outside the ring, Kevin Nash had the role of Super Shredder in "Teenage Mutant Ninja Turtles II: The Secret of the Ooze." Additionally, he has appeared in "The Punisher" (2004), "The Longest Yard" (2005), a 1997 episode of "Sabrina, The Teenage Witch," and a very short-lived comic book titled "NASH" (1999).
In his personal life, he forged a close friendship with Shawn Michaels, Scott Hall, Sean Waltman, and HHH, known professionally as The Kliq, which served as a precursor of the nWo and Degeneration X, even though they never appeared on television as a unit.
Kevin Nash made etWo history when he stumbled off an elevator in Los Angeles, CA, and he encountered three drunk members of the etWo, who proceeded to exclaim "Hiii Kevin Nassh!?" and to inform him that the liquor store was open for another ten minutes.