On March 27, 2007, Gargano appeared as the "Champion of Liechtenstein", Cedrick Von Haussen, on an episode of World Wrestling Entertainment's television program SmackDown!, losing to Montel Vontavious Porter. He made another appearance for WWE on the May 25, 2010, edition of NXT, portraying a security guard. Gargano wrestled another tryout for WWE, now working under the ring name Joey Gray, at the September 20, 2011, tapings of Superstars, losing to Brodus Clay.
In June 2015, Gargano took part in a WWE tryout camp, and also wrestled at the June 18 NXT tapings, losing to Uhaa Nation. Though he did not sign with WWE, Gargano continued making appearances for NXT over the next few months. Most notably, he teamed with Tommaso Ciampa in the Dusty Rhodes Tag Team Classic tournament, defeating the team of Bull Dempsey and Tyler Breeze in their first round match on the September 9 episode. They were eliminated from the tournament by Baron Corbin and Rhyno on the September 16 episode. Gargano continued working for NXT in early 2016. On April 2, it was confirmed that Gargano had signed with WWE earlier in the week. On June 23, Gargano entered the Cruiserweight Classic tournament, defeating his tag team partner Tommaso Ciampa in his first round match. On July 14, Gargano was eliminated from the tournament by T.J. Perkins. On July 21, it was reported that Gargano was signing a new full-time NXT deal.
On August 20 at NXT TakeOver: Brooklyn II, Gargano and Ciampa unsuccessfully challenged The Revival (Dash Wilder and Scott Dawson) for the NXT Tag Team Championship. Gargano and Ciampa, now billed collectively as "DIY" (often stylized as #DIY), received another title shot in a two out of three falls match on November 19 at NXT TakeOver: Toronto, where they defeated The Revival to become the new NXT Tag Team Champions. DIY went on to successfully defend their championships against the team of Tajiri and Akira Tozawa and TM61 in Japan and Australia, respectively. They defeated The Revival in a rematch on the January 11, 2017 episode of NXT to retain the titles, but were attacked by The Authors of Pain (Akam and Rezar) afterwards. At NXT TakeOver: San Antonio, they lost the titles to The Authors of Pain. They received their rematch on the March 1 episode of NXT, which ended in a no contest after The Revival interfered and attacked both teams. This led to a triple threat elimination match between all three teams for the NXT Tag Team Championship at NXT TakeOver: Orlando, where DIY failed to regain the titles after being the first team eliminated.
On May 20 at NXT TakeOver: Chicago, DIY once again faced The Authors of Pain in the first-ever ladder match for the NXT Tag Team Championship, which they lost. After the match, Ciampa turned on Gargano to end the partnership between the two. Their feud continued when Gargano faced Andrade Cien Almas at NXT TakeOver: Brooklyn III but he lost after Almas valet, Zelina Vega, threw a #DIY shirt at Gargano to distract him. Gargano had a rematch with Almas on the October 11 episode of NXT, but lost again after Vega distracted him by wearing a #DIY shirt. On the December 6 episode of NXT, Gargano defeated Kassius Ohno to qualify for a number one contender's fatal four-way match for the NXT Championship involving Aleister Black, Killian Dain and Lars Sullivan, which Gargano won after pinning Black (becoming the first man to do so).
At the next NXT event, NXT TakeOver: Philadelphia, Gargano failed to capture the NXT Championship from Andrade "Cien" Almas. After the match, Ciampa returned to attack Gargano from behind with a crutch. Gargano faced Almas for the NXT Championship again on the February 21 episode of NXT, where Gargano failed to win the title after interference from Tommaso Ciampa, thus forcing him to (kayfabe) leave NXT. At NXT TakeOver: New Orleans, he defeated Ciampa in an unsanctioned match to be reinstated to NXT. On the April 25 episode of NXT, Gargano was once again attacked by Ciampa while he was making his entrance for his NXT Championship match against Aleister Black, leading to a Chicago Street Fight was scheduled between them at NXT TakeOver: Chicago II, which Ciampa won.
During his feud, his character began a darker turn, becoming more unstable, showing a more aggressive style and using a spike DDT to defeat EC3 on the July 4 episode of NXT, similar to the one that Ciampa pinned him with at TakeOver Chicago II. At the July 18 NXT tapings of July 25 episode, Gargano interfered in Ciampa's NXT Championship match against Black and accidentally hit Black with the title belt, causing Ciampa to win the championship. The following week, all three men were scheduled in a triple threat match for the NXT Championship at NXT TakeOver: Brooklyn IV, though Black was removed from the match due to being unable to compete after being found unconscious in the parking lot after the show. The title match was later changed to a Last Man Standing match between Gargano and Ciampa at the event. Gargano lost the match and, on the October 24 episode of NXT, was revealed as the one who attacked Aleister Black, becoming a heel in the process. Black and Gargano continued their rivalry and had a match at NXT TakeOver: WarGames II, which Black won.
On the December 19 episode of NXT, Gargano defeated Black in a steel cage match after interference from Ciampa. At NXT TakeOver: Phoenix, Gargano defeated Ricochet to capture the NXT North American Championship. Later in the night, after Ciampa successfully defended his NXT Championship against Black, Gargano reunited with his former tag-team partner as they raised their belts in unison on stage as the show went off air. The following night, he would make his first main roster appearance at the Royal Rumble event, entering at number 6 in the Royal Rumble match, in which he lasted over 13 minutes and eliminated Jinder Mahal before getting eliminated by Dean Ambrose. On January 30, Gargano defended the North American Championship against Velveteen Dream during the NXT tapings, where he lost the title.
Gargano made his main roster debut on the February 18, 2019, episode of Raw with three other fellow NXT stars – Ricochet, Ciampa and Black. In his main roster debut, he and Ciampa defeated former rivals Raw Tag Team Champions The Revival in a non-title match. The next night on their SmackDown debut, Gargano and Ciampa defeated The Bar (Cesaro and Sheamus). On the March 13 episode of NXT, after Gargano and Ciampa were eliminated from the Dusty Rhodes Classic, Ciampa attempted to attack Gargano, similar to his original betrayal at TakeOver: Chicago two years prior, before Gargano reversed it and attacked him, thus turning face.
On the March 20 episode of NXT, it was revealed by Triple H that Gargano and Ciampa were to compete at NXT TakeOver: New York for the NXT Championship, but it was revealed that Ciampa needed real-life neck surgery, thus removing from the match and forcing him to vacate the title; therefore, it was announced that Gargano would still be in the match for the now vacant title, and his opponent would be Adam Cole, who won a fatal five-way match later that night to earn the right to replace Ciampa.
At the event, Gargano defeated Cole in a two-out-of-three falls match to win the NXT Championship for the first time in his career, also becoming the first NXT Triple Crown Champion. At the end of the show, Ciampa came out to celebrate Gargano's successful title win with Candice LeRae as well. On the April 17 episode of NXT, Gargano was celebrating his championship victory until he was confronted and attacked by The Undisputed Era. A rematch was scheduled between Gargano and Cole to take place at NXT TakeOver: XXV, where Gargano lost the title. Gargano's rematch at NXT TakeOver: Toronto was then scheduled by William Regal to be a two-out-of-three falls match, with each wrestler allowed to pick a stipulation, with Regal deciding the final fall's stipulation. Gargano, however, was unsuccessful in his efforts, losing to Adam Cole, with the final fall being in a steel cage match, after Gargano and Cole plummeted off the top of the cage, both men going through a table.
On the October 23 episode of NXT, Gargano reunited with Ciampa once again, only to be attacked by The Undisputed Era and surprise NXT returnee Finn Bálor; he suffered a legitimate neck injury when Bálor performed his signature move 1916 on Gargano on the entrance ramp, sidelining him indefinitely. He returned on the December 18 episode of NXT, distracting Bálor during his NXT Championship match against Adam Cole, causing him to lose; he then attacked Bálor with a steel chair post-match. On the January 8, 2020 episode of NXT, Bálor challenged Gargano to a match at NXT TakeOver: Portland, which Gargano accepted. At the event, Gargano was defeated by Bálor, and later that same night, Gargano interfered in the main-event between Cole and Ciampa for the NXT Championship and attacked Ciampa with the title belt while the referee was unconscious, which subsequently allowed Cole to pin Ciampa, thus breaking up DIY for the second time, turning heel in the process. Gargano would justify his actions by stating that Ciampa stole his moment and put him through hell for two years. This culminated in an empty arena No Holds Barred match between the two on the April 8, 2020 episode of NXT, where Gargano defeated Ciampa after Candice gave Ciampa a low blow and Gargano hit Ciampa with the Fairytale Ending. On the April 29 episode of NXT, Gargano accompanied LeRae to the ring as she defeated Kacy Catanzaro. On the May 6 episode of NXT, Gargano debuted a new titantron and theme to match his heel turn as he defeated Dominik Dijakovic. Gargano and LeRae began appearing together more frequently as a power couple as they feuded with Mia Yim and Keith Lee. At NXT TakeOver: In Your House, Gargano challenged Lee for the NXT North American Championship, but was unsuccessful. On the June 24 episode of NXT, he faced Lee and Balor in a triple threat match for the North American Championship, where the winner would go on to face Adam Cole for the NXT Championship, but was once again defeated.
At NXT The Great American Bash, Gargano defeated Isaiah "Swerve" Scott in singles competition. On the July 22 episode of NXT, Gargano faced Bronson Reed and Roderick Strong in a triple threat qualifying match to earn a spot in the NXT North American Championship match at NXT TakeOver: XXX, but lost to Reed. However, after Dexter Lumis dropped out of the ladder match following an ankle injury. Gargano would replace Lumis after a last chance match against Ridge Holland, which he won. At NXT TakeOver: XXX, Gargano would fail to win the title. It was announced on the August 25 episode of NXT that Gargano would be one of the men competing in the fatal four-way Iron Man match on the September 2 episode of NXT for the vacant NXT Championship. He was unsuccessful at capturing the title as the match ended in a time limit draw. On October 28 at NXT Halloween Havoc, Gargano defeated Damian Priest to win the NXT North American Championship for the second time. He would then lose the title to Leon Ruff on the November 11 episode of NXT, but regained it at NXT TakeOver: WarGames in a triple threat match, involving Priest, to become the first-ever three-time NXT North American Champion. He then revealed on the December 9 episode of NXT that he had formed a villainous faction with LeRae, Indi Hartwell and Austin Theory called The Way. On the December 30 episode of NXT, Gargano successfully retained his title against Ruff, finally breaking his championship "curse". At NXT TakeOver: Vengeance Day, Gargano successfully retained the title against Kushida.
At NXT TakeOver: Stand and Deliver, Gargano retained the title against Bronson Reed. On the May 18 episode of NXT, he lost the title to Reed in a steel cage match, ending his reign at 163 days. At NXT TakeOver: In Your House, Gargano failed to capture the NXT Championship in a fatal five-way match which involved Adam Cole, Karrion Kross, Kyle O'Reilly, and Pete Dunne. On the July 13 episode of NXT, Gargano faced Kross for the NXT Championship with Samoa Joe as guest referee, but was defeated.
On the August 3 episode of NXT, Gargano competed in a "Love Her or Lose Her" match with Dexter Lumis for Indi Hartwell. Hartwell came out to ringside before Gargano pinned Lumis, and as The Way were walking to the backstage area, Hartwell ran back to the ring and pounced on Lumis despite the stipulation. On the October 19 episode of NXT, Gargano turned face for the first time since February 2020 when he confronted new NXT North American Champion Carmelo Hayes and Trick Williams, only for the pair to insult Hartwell, leading to Gargano and Lumis attacking the pair and stealing Hayes's Championship. On October 26, at Halloween Havoc, Gargano and Lumis lured Hayes and Williams to Dexter Lumis's haunted house, where Hayes's NXT North American Championship was hidden. On the November 23 episode of NXT 2.0, Gargano faced Hayes and Pete Dunne in a triple threat match for the title, in which Hayes retained due to interference from Tony D'Angelo. After the match, Gargano, Dunne, Tommaso Ciampa, and LA Knight would brawl with Hayes, D'Angelo, Bron Breakker and Grayson Waller, leading to a WarGames match at NXT WarGames. Before that on the November 30 episode of NXT 2.0, Gargano faced Breakker in a WarGames advantage ladder match, but was defeated. At the event, Gargano's team, known as Team Black and Gold, would be defeated by Team 2.0. On the following episode of NXT 2.0, Gargano cut a farewell promo where he thanked his fans, friends, and family before being brutally attacked by Grayson Waller. This would be Gargano's last appearance for WWE as he left on December 10.
On the August 22, 2022 episode of Raw, Gargano made his return after nearly nine months since leaving WWE to give a speech, but was interrupted by Theory. After being mocked by Theory, Gargano gave him a superkick and left Theory lying in the ring. Two weeks later on Raw, he wrestled against Chad Gable, winning by pinfall, but was attacked by Theory after the match. On the October 3 episode of Raw, Gargano suffered his first main roster loss to Otis after Theory hit him with his Money in the Bank briefcase. He retaliated by defeating Theory on the following episode of Raw, ending their feud. At Royal Rumble on January 28, 2023, Gargano competed in his second rumble match where he lasted nearly thirty minutes before being eliminated by Dominik Mysterio and Finn Bálor. On the following episode of Raw, Gargano defeated Baron Corbin to qualify for the Elimination Chamber for the United States Championship at the eponymous event, however he was unsuccessful in the Elimination Chamber match on February 18.
At NXT Roadblock on March 7, Gargano returned to the NXT brand as Shawn Michaels' specially selected opponent against Grayson Waller for NXT Stand and Deliver. At the event, Gargano defeated Waller. After a five month hiatus, Gargano returned on the October 2 episode of Raw by saving Tommaso Ciampa from an attack by Imperium, reforming DIY. On the January 29, 2024 episode of Raw, DIY received a match for the Undisputed WWE Tag Team Championship against The Judgment Day's Damian Priest and Finn Bálor, but were defeated. On the March 18 episode of Raw, DIY defeated The Creed Brothers to qualify for the six-pac ladder match for the Undisputed WWE Tag Team Championships at WrestleMania XL, which they were unsuccessful. On the April 17 episode of WWE Speed, Gargano defeated Legado del Fantasma's Angel in the quarterfinals of the tournament to crown the inaugural WWE Speed Champion. On the April 22 episode of Raw, DIY was unsuccessful in winning the World Tag Team Championship from the Awesome Truth (The Miz and R-Truth).
On night two of the 2024 WWE Draft, both Gargano and Ciampa were drafted to SmackDown. On the May 1 episode of Speed, Gargano defeated Bronson Reed in the semifinals of the tournament to crown the inaugural WWE Speed Champion. On the July 5 episode of SmackDown, Gargano and Ciampa became the new WWE Tag Team Champions by defeating A-Town Down Under (Austin Theory and Grayson Waller). On the August 2 episode of SmackDown, DIY lost the titles to The Bloodline (Jacob Fatu and Tama Tonga) after interference from Solo Sikoa and Tonga Loa, ending their reign at 28 days.