In May 1986, Race entered the WWF managed by longtime friend Bobby "The Brain" Heenan, bleaching his hair blond and billing himself again as "Handsome" Harley Race. During a time when the WWF did not recognize the existence of other promotions and the accomplishments a wrestler made there, WWF officials came up with a solution to recognize his wrestling pedigree by having him win the King of the Ring tournament. After this, he referred to himself as "King" Harley Race, coming to the ring in a royal crown and cape, to the ceremonial accompaniment of the tenth movement (known as "The Great Gates of Kiev"). After winning a match, Harley would make his defeated opponent "bow and kneel" before him. Usually Bobby Heenan would assist the defeated opponent to "bow and kneel" by grabbing their hair and forcing them to bow before King Harley Race.
He participated in a notable feud with the Junkyard Dog, culminating in a match at WrestleMania III at the Pontiac Silverdome, in which Race cleanly pinned The Junkyard Dog. Race would spend 1987 feuding with Hulk Hogan and Jim Duggan, the latter of which was highlighted by an extended brawl at the 1987 Slammy Awards. In early 1988, he suffered an abdominal injury in a match against Hogan in which he tried to hit Hogan, prone on a table at ringside, with a swandive headbutt. Hogan moved out of the way and Race impacted the table inwards. The metal edge forced its way up into Race's abdomen giving him a hernia. Following this incident and during his recovery, the WWF ran an angle where they acknowledged his injury, and his manager Bobby Heenan vowed to crown a new king. He left the WWF in early 1989, following a brief comeback from hernia surgery and a failed attempt to regain his crown from the new King, Haku, at the Royal Rumble). He had many backstage roles during the 90's, including at Over the Edge 1999 the night of Owen Hart's death. This is stated in the documentary "The Life and Death of Owen Hart" in which Race states that he bumped into Owen, and that Owen told him he was uncomfortable with his new equipment for the stunt. While Race never won the WWF Championship, his career was notable enough to earn him an induction into the WWE Hall of Fame in 2004.
Race returned to WWE television as a fan favorite in 2004 shortly after being inducted into their Hall of Fame. On an episode of Raw, Randy Orton confronted Race and spat in his face, to go with Orton's "Legend Killer" persona . Race returned again for Raw's WWE Homecoming episode in October 2005, marking the show's return to the USA Network. Race, along with the other legends who were in the ring, gave Rob Conway a lesson in respect.
At the WWE Hall of Fame ceremony on March 31, 2007, Race and Dusty Rhodes were "inducted" into the Four Horsemen by Ric Flair and Arn Anderson. On the August 8, 2008 episode of Monday Night Raw, Race sat in the front row and was acknowledged by commentators Michael Cole and Jerry "The King" Lawler. Before the show, Race accompanied then Takeshi Morishima to the ring for a dark match against Charlie Haas.
Race made a special appearance on the March 31, 2008 episode of Raw as part of Ric Flair's retirement ceremony. He was the fourth person introduced to congratulate Flair after the Four Horsemen (Arn Anderson, Tully Blanchard, Barry Windham and James J. Dillon), Batista and Ricky Steamboat.
Race appeared at August, 27th, 2011 edition of SmackDown live event in Cape Girandeau, Missouri and introduced Ted DiBiase, Jr., who trained nearby at his school. DiBiase gave thanks to Harley, and told him he is living his dream before losing to Sin Cara.