Matt and Jeff Hardy debuted in the World Wrestling Federation (WWF) as jobbers both in singles and tag team competition.
The Hardy Boyz started their run as a popular tag team with a win over Kaientai (Mens Teioh and Sho Funaki) on the September 27, 1998 episode of Sunday Night Heat. Soon after their Sunday Night Heat win, they built up a fan base following through their high-flying tag team tactics. They started to become serious contenders for the WWF Tag Team Championship after they adopted the managerial services of Michael Hayes. On the June 29, 1999 episode of Raw is War (aired July 5), they defeated The Acolytes (Faarooq and Bradshaw) to win their first WWF Tag Team Championship, but they re-lost the title to The Acolytes a little less than a month later at Fully Loaded.
They eventually dumped Hayes as their manager in August 1999, becoming villains and briefly associating themselves with Gangrel as part of The New Brood. After winning a series of matches against the team of Edge and Christian—dubbed the Terri Invitational Tournament—they won the services of Terri Runnels as their manager by winning the first ever tag team ladder match at No Mercy, and then dumped Gangrel the next night, becoming faces. The fans also gave both teams a standing ovation the next night on Raw is War. This began an over two year rivalry between the Hardy Boyz and the team of Edge and Christian. During this time, they also gained notoriety as a faction with Lita.
With the addition of Lita, Matt and Jeff comprised the trio dubbed Team Xtreme, their name serving as a reflection of their "extreme" high-flying moves. In 2000, they were involved in feuds with Edge and Christian and The Dudley Boyz (Bubba Ray Dudley and D-Von Dudley) in many ladder matches and TLC matches.
They faced Edge and Christian and the Dudley Boyz at WrestleMania 2000 in a triple threat tag team ladder match. The Dudley Boyz started the match as the champions and Edge and Christian won the titles. The Hardyz faced Edge and Christian for the titles at Insurrextion and defeated them by disqualification, which meant that Edge and Christian retained the titles. At King of the Ring, the Hardy Boyz squared off in a four corners elimination match for the WWF Tag Team Championship which included the champions Too Cool (Grandmaster Sexay and Scotty 2 Hotty), T&A (Test and Albert) and Edge and Christian. The Hardyz were able to eliminate T&A before getting eliminated themselves by Edge and Christian.
At SummerSlam, the Hardy Boyz were defeated in the first ever TLC match for the titles, which Edge and Christian won, and in which the Dudley Boyz also competed. At Unforgiven, the Hardy Boyz defeated Edge and Christian in a steel cage match to win the titles for a second time. They re-lost the titles to Edge and Christian (who were dressed as Los Conquistadores) at No Mercy, but they won it back the next night on Raw is War for a third time. During the match, the Hardy Boyz were dressed as Los Conquistadores, but tore off their masks after the match, revealing themselves. The team lost the titles less than a month later to Right to Censor (Bull Buchanan and The Goodfather) on the November 6 episode of Raw is War, when Edge and Christian came out and assaulted the Hardyz, allowing Right to Censor to pick up the win and the title.
The Hardyz became involved in a feud with both Edge and Christian and Right to Censor. At Survivor Series, the Hardyz, along with the Dudleyz, defeated Edge and Christian and Right to Censor in a Survivor Series elimination match. At Rebellion, the Hardy Boyz faced Right to Censor in a rematch for the titles but were unable to win the titles when Val Venis interfered. On the December 4 episode of Raw is War, Dean Malenko defeated the Hardy Boyz' valet Lita to retain the Light Heavyweight Championship and earn himself a date with her three days later on SmackDown!, when Malenko took Lita on a date and received a beating from the Hardyz. The Hardyz began feuding with Malenko and his friends, The Radicalz (Eddie Guerrero, Chris Benoit, Malenko and Perry Saturn). The two teams faced each other in several tag team and singles matches on Raw is War and SmackDown!. The two teams also squared off against each other at Armageddon with Guerrero, Malenko and Saturn taking on the Hardyz and Lita; The Radicalz won the match.
On the March 5, 2001 episode of Raw is War, the Hardy Boyz captured their fourth WWF Tag Team Championship when they defeated The Dudley Boyz, after interference from Christian, only to lose the titles to Edge and Christian two weeks later on Raw. The next month at WrestleMania X-Seven, the Hardy Boyz competed in another TLC match against Edge and Christian and the Dudley Boyz. Just as in the first TLC match, Edge and Christian were victorious thanks to help from Rhyno.
On the October 8 episode of Raw, the Hardy Boyz won the WCW Tag Team Championship from Booker T and Test. They lost the titles to the Dudley Boyz two weeks later on SmackDown!. On the November 12 episode of Raw, they beat Booker T and Test again, but this time for the WWF Tag Team Championship. At Survivor Series, they lost the titles to the Dudleys in a steel cage title unification match. This defeat led to a break up storyline that resulted in a match between the brothers at Vengeance. Jeff would emerge victorious after Lita, who was the special referee, failed to see Matt's foot on the rope. The storyline was dropped in January 2002 and they reunited.
At No Way Out, the Hardy Boyz participated in a tag team turmoil match which was won by the A.P.A.. At WrestleMania X8, along with the A.P.A. and the Dudley Boyz, the Hardyz challenged Billy and Chuck for the WWE Tag Team Championship in a four corners elimination match. The A.P.A. were eliminated by the Dudleyz, whom the Hardy Boyz managed to eliminate. In the end, they were pinned by the champions, therefore losing the opportunity. They then began a feud with the newcomer Brock Lesnar and his manager Paul Heyman. At Judgment Day, the Hardy Boyz lost to Lesnar and Heyman in a tag team match.
The duo split up afterward as Jeff began a storyline with The Undertaker, while Matt was relegated to working on Heat. In the storyline, Matt then attacked Jeff due to jealousy of Jeff getting opportunities, including a match for the Intercontinental Championship. Matt was then moved to the SmackDown! brand, where he dubbed himself "Matt Hardy Version 1" and the "Sensei of Mattitude" and picked up Shannon Moore and briefly Crash Holly as followers. Jeff was released from WWE on April 22.
On August 4, 2006, Jeff rejoined WWE on its Raw brand. In November 2006, it was announced on WWE's official website that Matt and Jeff would team up for the first time together in over four years as members of Team DX at Survivor Series. The Hardys, as they were now known, were first given a "warm up match" on ECW on Sci Fi, defeating The Full Blooded Italians (Little Guido Maritato and Tony Mamaluke). At Survivor Series, Team DX defeated Team Rated-RKO in a clean sweep.
On the November 27 episode of Raw, The Hardys had their first shot at tag team gold in five years. They took on World Tag Team Champions Rated-RKO (Edge and Randy Orton), but came up short when Edge hit Jeff in the back with a belt to get himself and Orton deliberately disqualified to retain the title. That same day, The Hardys posed an open challenge to any team for the ECW brand's December to Dismember, which was immediately accepted by a reuniting MNM (Johnny Nitro and Joey Mercury). After a run in on the intervening ECW on Sci Fi, The Hardys defeated MNM at the event, starting a feud between all four men that spanned both brands. The Hardys got their first chance to gain the WWE Tag Team Championship at Armageddon, where the original tag team match was changed to a four team ladder match involving The Hardys, MNM, Dave Taylor and William Regal, and Paul London and Brian Kendrick. Despite coming up short, The Hardys sparked another feud with MNM when Mercury was legitimately injured. While Jeff and Nitro continued battling over the Intercontinental Championship on Raw, Matt and Mercury feuded on SmackDown!. Mercury and Nitro tried injuring both Hardys' faces as payback for what happened at Armageddon, claiming that The Hardys had ruined Mercury's 'Hollywood good looks'. The Hardys settled their feud with MNM at the Royal Rumble when they defeated them for the second time. Matt and Mercury continued feuding, however, which was finally settled at No Way Out.
On the April 2, 2007 episode of Raw, the Hardys won the World Tag Team Championship for the sixth time in their career after winning a ten-team battle royal. After losing singles bouts to both Lance Cade and Trevor Murdoch, The Hardys retained their World Tag Team Championship at both Backlash and Judgment Day against the team of Cade and Murdoch. At One Night Stand, the Hardyz retained the titles against The World's Greatest Tag Team (Charlie Haas and Shelton Benjamin) in a ladder match. The next night on Raw, however, the Hardys lost their championship to Cade and Murdoch, when Jeff missed a Swanton Bomb and was pinned by Cade after Murdoch pushed his foot off of the bottom rope of the ring. Cade and Murdoch attacked the Hardys with the championship belts after the match. The Hardys got a rematch at Vengeance, but was unsuccessful after Jeff was hit with a sitout spinebuster from Cade.
The Hardys once again returned to WWE on the November 13 episode of ECW to face Montel Vontavious Porter (MVP) and Mr. Kennedy, a match that was originally scheduled for the November 16 episode of SmackDown!. The Hardys were unsuccessful in their return as Porter pinned Jeff for the win. The Hardys, announced and referred to once again as the Hardy Boyz, reunited once again in 2008, on the June 23 episode of Raw in a losing effort to John Morrison and The Miz. The match occurred after Jeff was drafted to the SmackDown brand (the same brand as Matt). This loss, however, caused Matt to be drafted to the ECW brand. On the July 15 episode of ECW, The Hardys reunited in their home state of North Carolina, defeating Morrison and Miz. The Hardys then teamed up on the October 31 episode of SmackDown and on November 3 on Raw, winning both matches.
The Hardy Boyz kickstarted 2009 with a win over Edge and Big Show on the January 2 episode of SmackDown. Heading into the 2009 Royal Rumble, Matt was attempting to regain the ECW Championship from Jack Swagger while Jeff held the WWE Championship. After Matt lost to Swagger, he interfered in Jeff's match with Edge, hitting Jeff with a steel chair and allowing Edge to win the WWE Championship. On the January 30 episode of SmackDown, Matt announced the permanent disbandment of the tag team due to the events at the Royal Rumble and that he no longer considered Jeff as his partner or brother. Matt moved to the SmackDown brand and began a scripted rivalry with Jeff. The pair faced each other in an Extreme Rules match at WrestleMania XXV, which Matt won. They later faced each other in a stretcher match, in which Matt gained his second win over Jeff. As part of the 2009 WWE draft, Matt was drafted to the Raw brand on the April 13 episode of Raw. Despite this, the brothers faced each other in an "I Quit" match at Backlash, which Jeff won. Matt also interfered in Jeff's World Heavyweight Championship match at Judgment Day, preventing him from winning the championship.
On the August 21 episode of SmackDown, Jeff (then-the World Heavyweight Champion) and Matt reunited as the Hardys and teamed with John Morrison in a six-man tag team match to defeat CM Punk and The Hart Dynasty. The following week, Jeff lost a "Loser Leaves the WWE" steel cage match to CM Punk, resulting in him leaving the company. Over a year later, on October 15, 2010, WWE announced that Matt had been released from his contract.
On April 2, 2017, at WrestleMania 33, The Hardy Boyz made an unannounced return to WWE, after hosts The New Day (Big E, Kofi Kingston and Xavier Woods) announced that the triple threat ladder match for the Raw Tag Team Championship, which had been set by WWE before the event was now going to be a fatal four-way match. They then began jokingly questioning the arena about who the mystery team could be, before the Hardy Boyz's made their entrance to the stage to a massive ovation from the crowd. At the event, The Hardy Boyz won the Raw Tag Team Championship, defeating the teams of Enzo Amore and Big Cass, Cesaro and Sheamus, and then-reigning champions Luke Gallows and Karl Anderson. The night after WrestleMania, on Raw, they successfully defended the Raw Tag Team Championship against Luke Gallows and Karl Anderson. Afterwards on Raw Talk, Matt mentioned that the Hardy Boyz had successfully completed the Expedition of Gold after winning the Raw Tag Team Championship. They would retain the titles at Payback against Sheamus and Cesaro, but lost them at Extreme Rules in a steel cage match, and failed to regain it at the inaugural Great Balls of Fire event.
In September, Jeff suffered a torn rotator cuff and would be out of action for four to six months, leaving Matt to begin a run as a singles competitor. One year later, on the February 26, 2019 episode of SmackDown Live, the Hardy Boyz reunited and, on the April 9 episode of SmackDown, defeated The Usos to win the SmackDown Tag Team Championships. With this, they became the first team to win all three of WWE's world tag team championships (World, Raw, and SmackDown). However, they vacated the WWE SmackDown Tag Team Championships due to Jeff suffering a leg injury from Lars Sullivan. While Jeff was recovering, Matt was featured less on WWE television until he left WWE on March 2, 2020.