On October 19, 1998, Daivari appeared on WCW Nitro as a fan being interviewed by Mike Tenay.
Daivari appeared on the October 5, 2003 episode of Sunday Night Heat as Shawn Daivari, losing his match against Tommy Dreamer.
Daivari signed a contract with World Wrestling Entertainment (WWE) in August 2004 and debuted on the December 13 episode of Raw alongside Muhammad Hassan as Khosrow Daivari, later shortened to Daivari. Their gimmick was that of two Iranian Americans who were tired of the prejudice and stereotypes they were receiving after the 9/11 attacks. In the weeks leading up to their debut, the two men would appear on Raw in vignettes promoting their hatred towards "America". In the following weeks, they would back up their words with actions, initiating a feud with Raw announcers Jim Ross and Jerry "The King" Lawler. At WrestleMania 21 on April 3, 2005, Daivari and Hassan were involved in an angle with Hulk Hogan. While attacking injured wrestler Eugene, Hogan came to the ring and ejected both men from the ring.
The following night on Raw, Daivari and Hassan interrupted Shawn Michaels during a promo. The two attacked Michaels and left him helpless in the ring. This led to Daivari's first singles match in WWE, on the April 11, 2005, episode of Raw. Although Michaels was heavily favored, Daivari, with help from Hassan, got the upset win. Enraged, Michaels demanded a match against both Daivari and Hassan. Raw General Manager Eric Bischoff refused to grant a handicap match, but instead ordered Michaels to find a partner. That partner turned out to be Daivari and Hassan's WrestleMania foe Hulk Hogan.
On the April 18, 2005, episode of Raw, Michaels was once again double teamed by Daivari and Hassan until Hogan appeared to make the save. Hogan accepted Michaels' offer to tag and the match was set for the Backlash pay-per-view on May 1, 2005. At Backlash, Hogan and Michaels picked up the win which led to friction between the two since Hassan blamed Daivari for the loss. The next night on Raw, Hassan verbally and physically attacked Daivari leaving their future as a team in question.
Both Daivari and Hassan were later drafted to SmackDown! on June 23, 2005, as part of a package deal. On the July 7, 2005 episode of SmackDown!, then-General Manager Theodore Long put Daivari in a match against The Undertaker for that night, and Muhammad Hassan in a match against The Undertaker at The Great American Bash. Daivari was squashed easily in that match, after which Hassan began to pray on the ramp, summoning five masked men to the ring. The masked men beat and strangled The Undertaker into submission, and Hassan put him in the camel clutch. Afterward, the masked men carried Daivari off like a martyr. After Hassan lost in a match with The Undertaker, Hassan was given the Last Ride through an open stage ramp onto a concrete floor. It was reported that he sustained serious injuries and had to be rushed to a nearby medical facility; this was an angle aimed to "end" the character.
On November 7, 2005, Daivari returned to Raw, acting as Kurt Angle's anointed special guest referee in the tag team match between Shawn Michaels and John Cena against Angle and Chris Masters. During the match, Daivari favored Angle and Masters, who won the match via disqualification when Michaels was caught with a chair Angle brought in.
On November 21, 2005, Kurt Angle announced that Daivari was to be the referee for all his future matches, including his WWE Championship match against John Cena for the title at Survivor Series. Mr. McMahon rescinded that at the kangaroo court trial of Eric Bischoff on Raw on December 5, 2005. Daivari remained aligned with Kurt Angle as his manager.
On the January 13, 2006, episode of SmackDown!, Angle and Daivari were drafted to SmackDown!, where Angle won the World Heavyweight Championship that same night. Angle later revealed that his contract on Raw had expired, which allowed them to switch brands. Angle was already signed to face Shawn Michaels on Raw, however this non-title match went ahead, but Daivari would accidentally cost Angle the match against Michaels. Afterwards, Daivari and Angle argued, but when Daivari slapped Angle, he was Angle Slammed over the ropes and down to the floor on the outside of the ring. During the break, on WWE.com's Unlimited, an enraged Angle made it known that Daivari's services were no longer needed.
A short time later, Daivari faced his former client in a match, during which Mark Henry, the number one contender for Angle's title, attacked Angle. After the match, Daivari officially announced that he was now managing Henry and continued to manage Henry during his feud with The Undertaker. Daivari would not be seen on television in the weeks leading up to WrestleMania 22 when, at Saturday Night's Main Event XXXII, he suffered a chokeslam and Tombstone Piledriver at the hands of The Undertaker onto the lid of a casket.
On the April 7, 2006, episode of SmackDown!, Daivari made his return bringing in the debuting The Great Khali to attack The Undertaker during his match with Mark Henry. The next week, Daivari officially presented him to the crowd, hyping him as an "unstoppable monster". Over the following weeks, Daivari would accompany Khali to the ring as he attacked various SmackDown! superstars. This would all lead up to a match with The Undertaker at Judgment Day on May 21, 2006, which Khali would end up winning. Daivari and Khali appeared as guests on Piper's Pit on the June 2, 2006, episode of SmackDown!, in which Roddy Piper made fun of Khali, who supposedly couldn't speak English. Eventually Piper stood on the bottom rope, attempting to match height with Khali, before Khali grabbed him by the throat. Daivari made Khali put Piper down and straightened Piper's jacket disrespectfully, at which Piper slapped Daivari, but was then given a chop by Khali. The Undertaker was the original guest on the Pit, but he declined the invitation a few days before. Daivari continued to accompany The Great Khali to the ring when Khali wrestled or attacked other wrestlers, but when The Great Khali became inactive due to injury, Daivari was taken off the road as well.
Daivari and The Great Khali were moved to the ECW brand officially when they made their debuts on the October 31, 2006, episode of ECW on Sci Fi, in which Daivari defeated "The Reject" Shannon Moore. Daivari's original theme music was used as well as his Persian rants on the microphone. Afterwards, Moore was manhandled by The Great Khali. Daivari continued his winning streak over the next several weeks with The Great Khali usually following up the contest with a chokebomb on Daivari's opponent. At December to Dismember on December 3, 2006, Daivari got a victory over Tommy Dreamer following a schoolboy roll-up. Dreamer then chased Daivari all the way to the back, but The Great Khali appeared and caught Dreamer, planting him on the steel ramp with a chokebomb. On January 8, 2007, The Great Khali debuted on Raw without Daivari. The following night, however, Daivari accompanied Khali to the ring for his match against Dreamer on ECW on Sci Fi.
Daivari returned to SmackDown! on February 9, 2007, defeating then-Cruiserweight Champion Gregory Helms in a non-title match. He wrestled in a Cruiserweight Open for the WWE Cruiserweight Championship at No Way Out, won by Chavo Guerrero. He then began wrestling in the Cruiserweight division. He was involved in a feud between Kane and The Great Khali, once again promoting Khali in March 2007. His first match against Kane involved him being dragged backstage by Kane's chain and hook, leaving his back with multiple bruises. A few weeks later, Daivari had a rematch with Kane and was again defeated.
Daivari returned to SmackDown! a few months later, teaming up with Chavo Guerrero and Jamie Noble against Jimmy Wang Yang, Paul London and Brian Kendrick in a losing effort. On the June 15, 2007, episode of SmackDown!, Daivari competed in a fatal four-way number one contender match for the Cruiserweight Championship, which he lost to Yang and also involved Shannon Moore and Noble.
Daivari was drafted back to Raw in the supplemental draft on June 17, 2007. He re-debuted on the June 18, 2007, episode of Raw, losing to Jeff Hardy. On the July 30, 2007 episode of Raw, Daivari was defeated by Cody Rhodes who had to win his match or else being fired from WWE. Daivari's losing streak continued when he failed to win the position of General Manager of Raw by being eliminated early in the battle royal the week after Rhodes defeated him. Daivari then started to get on a roll on Heat (Raw's sister show) being victorious against Super Crazy and "Hacksaw" Jim Duggan. His return to Raw on September 17, 2007 saw him lose to Duggan in a flag match.
On October 16, 2007, Daivari was released from his WWE contract.
On May 3, 2011, Daivari made his WWE return by competing in a dark match before the SmackDown tapings, losing to Ted DiBiase. Daivari made his second return to WWE in a segment at 2018's Greatest Royal Rumble in Saudi Arabia, where he and his brother, Ariya Daivari, were driven out of the ring by four new Saudi recruits. He was later hired by WWE as a producer in January 2019, but was eventually released on April 15, 2020. He returned as a producer on June 11, 2021.