Holly, as Erin O'Grady, lost four untelevised matches in Extreme Championship Wrestling (ECW), in November 1997, including a dark match at November to Remember.
He debuted in the World Wrestling Federation (WWF) as Crash Holly, the storyline cousin of Bob "Hardcore" Holly, on the August 16, 1999 episode of Raw is War. They became known as The Holly Cousins. Their relationship was a strained one, and Hardcore frequently threatened Crash. When they took the gimmick of claiming to be "super heavyweights", over 400 pounds each, Crash would carry a scale to ringside to "weigh in" before matches.
Crash made his pay-per-view debut at SummerSlam in August 1999, where The Holly Cousins wrestled in a Tag Team Turmoil match, won by the Acolytes Protection Agency.
On October 17, at No Mercy, The Holly Cousins defeated The New Age Outlaws by disqualification. The next night on Raw is War, they defeated The Rock 'n' Sock Connection for the WWF Tag Team Championship. They held the title until the November 4 SmackDown!, when they lost it to Mankind and his new partner, Al Snow.
In early 2000, Crash Holly joined the hardcore division. On the February 24 episode of SmackDown!, he defeated Test to begin his first of 22 Hardcore Championship reigns. He decreed that he must defend the championship twenty four hours a day, seven days a week, which later became known as the "24/7 Rule". This meant that the title was permanently contested, not just in sanctioned matches, and could change hands anywhere, anytime anyone pinned the champion, so long as a WWF referee counted the fall. Holly was frequently attacked by other wrestlers in unlikely locations, including an airport, a funhouse, a circus, and his hotel room. Although he was often pinned, he usually immediately regained the title. His most common tactic was to sneak a pin, often after the champion had been beaten down by someone else, and quickly run backstage, away from possible challengers. This turned him into a crowd favorite and earned him the nickname "The Houdini of Hardcore". He frequently defended the championship against non-wrestlers, including referees and road agents, like Gerald Brisco and Pat Patterson. He had a long feud with The Mean Street Posse (Pete Gas, Rodney and Joey Abs) over the title. He even lost, and quickly regained, the title against one of the Godfather's ho's.
At Rebellion, Crash defeated William Regal to win the WWF European Championship. He lost the title to Regal two days later. In late 2000, another of Crash's storyline cousins, Molly Holly, was introduced. In 2001, The Holly Cousins feuded with The Dudley Boyz. In the course of this feud, Molly began a romantic relationship with Spike Dudley, leading to internal disputes within each family, as well as a Romeo and Juliet-style angle between the six of them.
On the March 18, 2001 episode of Heat, Crash defeated Dean Malenko to win the Light Heavyweight Championship. He defended it on two episodes of Heat, against Funaki and Grand Master Sexay, before dropping it to the debuting Jerry Lynn on the April 29 episode. In May 2001, Holly and Hardcore briefly reunited as a lower card team.
When the WWF was renamed World Wrestling Entertainment and divided into two Raw and SmackDown brands, Holly was assigned to the Raw roster, where he had little success. He jumped ship to SmackDown! on the September 2, 2002 episode of Raw during a match with Jeff Hardy. Earlier, Raw General Manager Eric Bischoff was informed that a Raw wrestler would leave to reunite with a relative on SmackDown!, and ordered a beatdown on Hardy, who he wrongly suspected of planning to join his brother, Matt Hardy.
In his first SmackDown! match, on September 5, he defeated The Hurricane. He then feuded with Cruiserweight Champion Jamie Noble. On the October 3 SmackDown!, Noble defeated Holly to retain the title.
On the December 19 SmackDown!, Holly teamed with Bill DeMott to defeat Noble and Nunzio. After the match, DeMott turned on Holly and attacked him. This led to a match on the next SmackDown!, which DeMott won.
After being sidelined for four months, Holly returned on the April 24, 2003 episode of SmackDown!. He soon joined Matt Hardy and Shannon Moore in the Mattitude Followers (abbreviated "MF'er") stable. As Crash was Moore's alleged apprentice, Hardy also referred to him as a "Moore-on". His last several matches with the company were tag matches with Moore, as well as house show matches against newcomer Orlando Jordan.
On June 30, 2003, Crash was released from WWE.
On November 6, 2003, Holly passed away.