Orndorff signed with the World Wrestling Federation in late 1983 and made his debut in November of that year on Championship Wrestling. Starting in January 1984, Orndorff took on "Rowdy" Roddy Piper as his manager. Piper nicknamed Paul Orndorff "Mr. Wonderful", a nickname that stuck with him for the rest of his career. Orndorff made his WWF debut against Salvatore Bellomo on the night that Hulk Hogan defeated The Iron Sheik for the WWF World Heavyweight Title and "Hulkamania was born", January 23, 1984, in Madison Square Garden. Orndorff became one of the first people to challenge for the world title, shooting straight to the main event less than a month after his debut. Hogan disposed of the challenger and moved on while Orndorff fought a variety of opponents including the Intercontinental Champion Tito Santana. When Piper assaulted Jimmy Snuka on the set of Piper's Pit, Orndorff assisted the Rowdy One in his matches. Orndorff and Piper often faced Snuka and "The Tonga Kid" in tag team competition.
Near the end of 1984, Roddy Piper's assault on Cyndi Lauper brought Orndorff and Piper on a collision course with Hulk Hogan and Mr. T. Hogan's feud with Piper also meant that Orndorff was thrust back into the main event picture; he defeated Tony Atlas at The War to Settle the Score and then played a part in the main event. The fallout from The War to Settle the Score led to the creation of WrestleMania, with Hogan and Mr. T (backed by Jimmy Snuka) taking on "Rowdy" Roddy Piper and Paul Orndorff in the main event (with Bob Orton, Jr., as Piper and Orndorff's manager) Orton's interference at the end of the match backfired when he accidentally hit Orndorff with the cast on his arm, allowing Hogan to pin Orndorff and win the match for his team. Blaming Orndorff for the loss, Piper and Orton attacked him on Saturday Night's Main Event I. Later in the evening, Orndorff ran to the ring to even the sides when Piper and Orton were preparing to double team Hulk Hogan. He solidified his babyface status by publicly firing manager Bobby Heenan shortly afterwards.
Orndorff and Hogan started teaming up to feud with Piper and Orton, facing them in tag team competition all over the country. Orndorff's feud with Piper and Orton continued to rage on while Hogan started to defend his title against other contenders; Orndorff faced both Orton and Piper in individual competition, usually without a conclusive outcome. After Orndorff fired Bobby Heenan as his manager, Heenan placed a $25,000 bounty on Orndorff, payable to anyone who could injure him. When no one succeeded, Heenan upped the bounty to $50,000. One of the first men to try and claim the new, higher bonus was Roddy Piper himself, but their matches got so out of hand that Bruno Sammartino was appointed as a special referee in the hopes of keeping peace. Instead of keeping peace, Sammartino became a target for Orton and Piper, which led to Orndorff and Sammartino teaming up. Orndorff teamed with a variety of opponents in his fights with Piper and Orton, including André the Giant. In February 1986, Bobby Heenan used a match between Hulk Hogan and Don Muraco as an opportunity to have King Kong Bundy attack Hogan, setting up their WrestleMania 2 match. While Hogan fought off Bundy, Orndorff battled Don Muraco in a match that ended in a double count out.
Orndorff's frustrations were further fueled by Adrian Adonis, who took every opportunity that he could to mock Orndorff (including referring to him as "Hulk Jr."), saying that he had gone soft from teaming with Hogan. Adonis kept on irritating Orndorff, going so far as daring Paul Orndorff to prove just how close his relationship with Hulk Hogan really was. During a televised phone call to Hulk Hogan, Orndorff was told that Hogan was too busy training to come to the phone, something which aggravated Orndorff to no end. The next time that Hogan and Orndorff teamed up, against The Moondogs, Orndorff wrestled most of the match by himself in an attempt to upstage Hogan, scoring the winning pin. The next week, during a tag match where Hogan and Orndorff faced the massive duo of Big John Studd and King Kong Bundy, Hogan and Orndorff accidentally collided and Hogan knocked Orndorff off the apron. When Studd and Bundy started to double team Hogan, Orndorff did not help out; he looked like he had hurt his eye in the collision. It was not until Studd and Bundy had Hogan in a compromised position that Orndorff reentered the ring to fend off Studd and Bundy. Orndorff then helped Hogan to his feet and raised his hand in the air, only to give Hogan a clothesline followed by a piledriver.
Orndorff soon reunited with manager Bobby Heenan and again feuded with Hulk Hogan, and began using Hogan's theme music, "Real American", as his own entrance theme. Their matches included a memorable outdoor match in Toronto which drew an estimated 76,000 fans. After a series of matches with no clean outcome it was decided that Hogan and Orndorff would clash in a steel cage match on Saturday Night's Main Event IX. The cage match saw both Orndorff and Hogan climb over the top of the cage and touch the floor at the same time. After reviewing the footage it was decided that it was a draw and the match was restarted. Once the match restarted, Hogan easily exited the cage to win the match following a leg drop, ending their feud.
After the program with Hogan ended, Orndorff worked a reduced schedule for a few months before he was forced to take some time off because of an arm injury. While Orndorff was away from the WWF, Bobby Heenan brought in "Ravishing" Rick Rude to take Orndorff's place in the Heenan Family. Orndorff returned to the ring on June 2, 1987, in Buffalo, New York during a WWF Superstars taping. Orndorff (along with King Kong Bundy, who had been off television since WrestleMania III as well) returned to team with Hercules and King Harley Race in a victory against Mario Mancini, Don Driggers, Paul Roma, and Jim Powers. Orndorff received a babyface response from the crowd during his return, leading the WWF to change his character. He would fire Bobby Heenan two months later and begin a feud with Rick Rude. Orndorff took Oliver Humperdink as his manager in his fight with Rude and Heenan. Orndorff's last "big" appearance was at the inaugural Survivor Series on November 26, 1987, where he teamed with Hulk Hogan, Bam Bam Bigelow, Ken Patera, and Don Muraco to take on André the Giant, the One Man Gang, King Kong Bundy, Rick Rude, and Butch Reed. Early in the match, Rude eliminated Orndorff with a roll-up. His final match came on a house show on January 4, 1988 against Rick Rude in Augusta, Georgia.
On the May 26, 1990 episode of World Championship Wrestling it was announced that Paul Orndorff would be facing Arn Anderson at Clash of the Champions XI. Orndorff made his in-ring debut on June 9 in Beckley, West Virginia, defeating "Nasty" Ned Brady on Main Event. Orndorff quickly became affiliated with a group called the "Dudes with Attitudes" consisting of himself, Sting, Lex Luger, Junkyard Dog, and The Steiner Brothers. The Dudes backed Sting in his fight with the Four Horsemen. At Clash of the Champions XI, Orndorff defeated Anderson, and at the 1990 Great American Bash, Orndorff teamed up with the Junkyard Dog and El Gigante to defeat Arn Anderson, Barry Windham, and Sid Vicious by disqualification. Throughout the summer, Orndorff would face Anderson and defeat the WCW TV Champion by pinfall in several non-title matchups. He also defeated "Mean" Mark Callous in multiple house show encounters. His final WCW match came on August 26 in Chicago when he teamed with The Junkyard Dog in a losing effort against the tag-team champions Doom. Orndorff departed from the promotion that fall.
Orndorff returned to WCW in late 1992. In January 1993 he took on Cactus Jack, with the winner being manager Harley Race's chosen replacement for an injured Rick Rude at Clash of the Champions XXII. Race assisted Orndorff in the match and was quickly joined by Vader in his attack on Cactus Jack. After the match, Race declared that Paul Orndorff was his chosen man. Orndorff was pinned by Cactus Jack in a subsequent Thunderdome match; the two had an intense feud including a Falls Count Anywhere match at SuperBrawl III, which Cactus Jack won.
After the feud with Cactus cooled off, "Mr. Wonderful" set his sights on the vacant WCW World Television Championship. Orndorff signed up for a 16-man tournament beating 2 Cold Scorpio, Cactus Jack, Johnny B. Badd, and then Erik Watts in the finals to win his first title in WCW. Orndorff, the TV champion, and Rick Rude, the U.S. Champion, began teaming on a regular basis, including a pay-per-view victory over Dustin Rhodes and Kensuke Sasaki at Slamboree. During this time Orndorff also turned back the challenges of Ron Simmons and Marcus Alexander Bagwell, amongst others, holding on to his Television title by any means necessary. Orndorff defeated Bagwell controversially, using the second rope for leverage during the pinfall. The two would later go on to feud for the WCW World Tag Team Titles. Orndorff's World TV Title reign also included a successful defence against Shane Douglas and a disqualification loss to Johnny B Badd, after Maxx Payne violently interfered. This led to a brief six man tag team alliance between Orndorff, Payne, and Chris Benoit. On August 18, 1993, Orndorff's luck ran out as Ricky Steamboat won the title at Clash of the Champions XXIV. After unsuccessfully challenging Ricky Steamboat throughout the fall and winter of 1993, Orndorff moved into the tag team division.
After the 1993 WCW pay-per-view Battlebowl, Horsemen members Paul Roma and Arn Anderson faced the semi-regular team of Paul Orndorff and "Stunning" Steve Austin on WCW Saturday Night. During the match, Roma acted very indifferently to his tag team partner, sowing the seeds to his heel turn. Next, Roma teamed with Erik Watts to take on the team of Orndorff and Lord Steven Regal. This time, Roma took it a step further and attacked Erik Watts before announcing that he was now teaming with Paul Orndorff.
Under the tutelage of manager Masked Assassin, the team quickly began to work well together in a feud with Marcus Alexander Bagwell and 2 Cold Scorpio. In the following months, both Roma and Orndorff focused on their individual careers before reuniting around May. This time they wrestled without their manager and were officially known as "Pretty Wonderful". With both men rededicated to teaming, they soon challenged for the WCW World Tag Team Championship then held by Cactus Jack and Kevin Sullivan. One incident especially stands out that established Pretty Wonderful in the title chase. The champions had one last defense against former champions the Nasty Boys that also saw Kevin's injured brother Dave. The match degraded into a brawl that saw Pretty Wonderful make an appearance using Dave's crutch to attack the champions. Before the team left the ring, they also took a couple of shots at the Nasty Boys for good measure.
Going into Bash at the Beach, Pretty Wonderful had the advantage as both champions were suffering from injuries inflicted by the challengers on previous occasions. Cactus Jack and Kevin Sullivan were unable to hold off Roma and Orndorff, as Pretty Wonderful left the ring with the gold. Pretty Wonderful was immediately challenged by the Nasty Boys after winning the title, but the Nasty Boys were never able to take the gold from the champions. Next, Pretty Wonderful was challenged by the duo of Stars and Stripes (Marcus Alexander Bagwell and The Patriot) at Fall Brawl. The champions retained, but a week later the championship changed hands when Stars and Stripes got the victory. Pretty Wonderful was granted a rematch against the new champions with a match booked for Halloween Havoc; Pretty Wonderful regained the titles when Roma used one of the title belts to knock Bagwell out cold.
During a February 5, 1995 taping of WCW Worldwide, Orndorff crossed paths with Hogan for the first time since 1987. The duo of Hulk Hogan and Randy Savage faced Pretty Wonderful in a televised match which the latter lost. This would be the only time that Orndorff and Hogan would be matched against each other during the latter's WCW run.
At Clash of the Champions XXIX, Stars and Stripes were granted a final shot at the tag team title, but the challengers also had to put up the Patriot's mask on the line. After a controversial double pin finish, Stars and Stripes were declared the winners and thus the champions, putting the end to Pretty Wonderful's second and final run with the gold.
Orndorff returned to singles competition with his most notable match at the time being an unsuccessful encounter when he faced the Great Muta at Slamboree. In May, Orndorff got a golden opportunity to regain the WCW Television title. He defeated Brian Pillman in a tournament to earn the shot at the champion. He lost to WCW newcomer The Renegade at Bash at the Beach. Orndorff was also unable to beat the rookie in subsequent matches and began to lose confidence in his abilities (storyline). After losing more and more matches, including a match on WorldWide to Randy Savage, Orndorff lost all faith in his abilities; the outwardly arrogant Mr. Wonderful was riddled with self-doubt, until one night, after beating himself up backstage after yet another loss, he was visited by psychic Gary Spivey. Spivey convinced Orndorff to believe in himself and that he shouldn't forget that he was "Mr. Wonderful". Orndorff became more arrogant than ever before and began carrying around a mirror everywhere he went.
On the December 11, 1995 episode of Monday Nitro, Orndorff confronted Brian Pillman after Pillman made derogatory comments about Orndorff. After telling Ric Flair and Anderson how much he respected them, Orndorff told Pillman that he could have been a Horseman and the only reason Pillman was a Horseman was because he turned it down. Anderson and Flair tried to calm Orndorff down but Orndorff lost his temper and attacked Pillman. Pillman, Flair, and Anderson attacked Orndorff and then Arn Anderson and Ric Flair delivered a spike piledriver to Orndorff on the arena floor during the attack. WCW later explained that Orndorff had been seriously hurt in the attack and that his career was over. At the 2000 Fall Brawl, in a match between The Filthy Animals and The Natural Born Thrillers, Orndorff suffered a neck injury after delivering a piledriver. The referee, Charles Robinson stopped the match as a result. He had a brief onscreen role during this time in the Old Age Outlaws with Terry Funk, Arn Anderson, and Larry Zbyszko to feud with the last WCW version of the nWo.
On February 3, 2005, Orndorff was announced as one of the inductees for the Class of 2005 into the WWE Hall of Fame. He was inducted on April 2 by Bobby Heenan.
On April 6, 2014, Orndorff made an appearance at WrestleMania XXX, marking the first time being on WWE television since the 2005 Hall of Fame. He appeared with Rowdy Roddy Piper, Hulk Hogan, Mr. T, Pat Patterson (who was part of the main event at the first WrestleMania) and Gene Okerlund (who was conducting an interview with Hogan when the rest appeared).
On August 11, 2014, Orndorff made an appearance at Hulk Hogan's birthday celebration on WWE Raw, celebrating in the ring with many other WWE legends, including Hogan himself, Ric Flair, Kevin Nash, Scott Hall, Gene Okerlund, Jimmy Hart, and Roddy Piper.
On July 12, 2021, Orndorff passed away.