In January 1993, Hogan joined the World Wrestling Federation as "The Predator". He made his televised debut on the January 31, 1993 episode of WWF Wrestling Challenge, losing to El Matador. This was his sole televised match in the WWF, as he competed exclusively at house shows for the remainder of his tenure. He was used primarily as a jobber, losing to wrestlers such as Jim Brunzell, Jim Powers, and Marty Jannetty. He made his final appearance with the WWF in August 1993.
In early 1995, he briefly performed with Extreme Championship Wrestling (ECW) under the ring name Prey of the Dead.
He debuted in World Championship Wrestling (WCW) in 1997. On the February 23, 1997 episode of WCW WorldWide, he, as Horace Boulder, defeated Mr. J.L.. At Spring Stampede 1998 on April 19, 1998, Boulder officially debuted, helping Raven defeat Diamond Dallas Page for the WCW United States Heavyweight Championship and joining Raven's Flock in the process. He remained in the Flock until the stable disbanded on September 13, 1998.
The fall of 1998 would hold one of the most crucial moments in Horace's wrestling career. Hollywood Hogan, backed by fellow New World Order (nWo) Hollywood members, revealed on the October 19, 1998 episode of WCW Monday Nitro that Horace was the son of his dead brother. Showing a sincerity not seen in previous years, he continued by proclaiming his love to his family and offering Horace a membership in the nWo. The mood quickly took a turn for the worse, however, when Hollywood Hogan bashed his nephew with a steel chair, causing a wound that would require several stitches. He continued by throwing his nephew off a stretcher and mercilessly beating him. During this time, Hogan was involved in a heated rivalry with The Ultimate Warrior, and this scene worked as a testament to Hulk's fragile state of mind.
Despite their unsettling confrontation, Horace joined the nWo at Halloween Havoc on October 25, 1998, by interfering on his uncle's behalf during the final match between Hollywood Hogan and The Warrior. Thereafter, he began using the ring name Horace Hogan to signify his blood ties with Hulk Hogan. He would wrestle for the nWo both in singles competition and tag teaming with the likes of Scott Norton, Stevie Ray, and Vincent, as well as Brian Adams in early 1999, where they came very close to winning the WCW World Tag Team Championship feuding with The Four Horsemen. Hogan also participated in a WCW Thunder battle royal for leadership of the nWo Hollywood faction. When the nWo Elite and B-Team began to dissolve in 1999, Horace began competing for the WCW Hardcore Championship.
Horace and his uncle began feuding with Billy Kidman and the New Blood in April 2000, with Horace helping Hogan defeat Kidman at Slamboree 2000 on May 7, 2000. Hogan defected to the New Blood, however, after the leader of the New Blood, Eric Bischoff, offered him Kidman's girlfriend Torrie Wilson in exchange for his assistance. Horace feuded with his uncle until the Great American Bash on June 11, 2000, when he refereed a rematch between Kidman and his uncle fairly, allowing his uncle to defeat Kidman after interference from Torrie who gave Hulk brass knuckles, which he would use to get the win. After Hulk Hogan left WCW in July 2000 due to a legitimate incident with Vince Russo that happened at that year's Bash at the Beach pay-per-view, Horace left the promotion.