In 1987, Warrior began competing for the WCWA Texas Heavyweight Championship, losing to Bob Bradley in a tournament final on January 12. He won the title from Bradley on February 2 of that year. The title was held up in April 1987 after Warrior left the WCCW. He was reinstated as champion upon returning, but vacated it once more upon resigning from WCCW to join the World Wrestling Federation, where he adopted the ring name The Ultimate Warrior. Warrior began appearing on house shows in June and was initially billed as The Dingo Warrior in house card promos by Gene Okerlund, but soon had his name modified. There is a dispute over who created the full Ultimate Warrior name. Bruce Prichard stated that Vince McMahon did not know what a "Dingo" Warrior was, but because there was the "Modern Day Warrior" Kerry von Erich and The Road Warriors there should not be one more simple warrior, but the ultimate warrior. Warrior claims after one of his first matches, McMahon had him do a pretaped promo. It was there Vince said we want you to do Warrior, but we don't want Dingo. The Warrior then proceeded to cut the promo and stated that he was not this warrior or that warrior, he was The Ultimate Warrior.
Between 1987 and 1989, he appeared in several TV ads for Westway Ford, a car dealership in Irving, Texas. Warrior interacted in full wrestling costume with Westway's wacky character, "Mean Joe Greed."
Hellwig joined the World Wrestling Federation (WWF) in June 1987. First competing on house shows under his Dingo Warrior moniker, he defeated a series of jobbers, including Steve Lombardi, Barry Horowitz and Mike Sharpe. He made his television debut as The Ultimate Warrior on the October 25 episode of Wrestling Challenge, where he defeated another jobber, Terry Gibbs. The Ultimate Warrior became known for his high-energy ring entrances, which featured him racing into the arena at full speed, bursting into the ring, and violently shaking the ropes up and down. He was also known for his distinctive pattern of face paint. After several months of defeating jobbers, he was pinned for the first time in the WWF by fellow WWF rookie/future rival Rick Rude on December 28, 1987. In early 1988, Warrior entered into his first real WWF feud with fellow strongman Hercules Hernandez. The two faced off on the February 7, 1988 airing of Wrestling Challenge, where Hercules was disqualified for using his steel chain. Warrior then grabbed a hold of the chain and in the midst of a tug of war over it, the chain snapped. This led to a match at WrestleMania IV, where Warrior was victorious in his pay-per-view debut. Warrior lost twice by pinfall shortly thereafter: cleanly to André the Giant in April in Italy, and to Dino Bravo, who put his feet on the ropes for leverage, in Montreal in June. In the summer of 1988, he wrestled Bobby Heenan in a series of weasel suit matches, in which Warrior won by sleeper hold.