On January 13, 2005, Strong made a one-off appearance on World Wrestling Entertainment's SmackDown episode. On the episode, Strong was defeated by Kurt Angle in Angle's "3-Minute Hometown Hero Challenge".
Strong made his NXT debut on the October 19, 2016 episode of NXT as Austin Aries' partner in the second Dusty Rhodes Tag Team Classic tournament, defeating Otis Dozovic and Tucker Knight. On October 25, 2016, WWE officially announced Strong as part of the latest group of recruits joining the WWE Performance Center. On the December 14 episode of NXT, Strong defeated Elias Samson, in doing so getting himself entered into a fatal four-way match to determine a new number one contender for the NXT Championship as well as establishing himself as a fan favorite. Strong competed in the fatal-four way on the December 21 episode of NXT, but was unsuccessful. Strong defeated Andrade "Cien" Almas at NXT TakeOver: San Antonio in his first TakeOver appearance.
Strong then began a rivalry with the faction SAnitY after coming to the aid of Tye Dillinger and No Way Jose, who were also battling the group. At NXT TakeOver: Orlando, Strong teamed with Dillinger, Ruby Riot and Kassius Ohno (replacing No Way Jose who had been attacked earlier in the night) to take on SAnitY in an 8-person mixed tag team match in a losing effort. On May 20, at NXT TakeOver: Chicago, Strong defeated Eric Young, giving Young his first pinfall loss in NXT. On the July 5 episode of NXT, Strong challenged Bobby Roode for the NXT Championship, but lost the match. After Drew McIntyre won the NXT Championship from Roode at NXT TakeOver: Brooklyn III, Strong defeated Roode on the August 30 episode of NXT. Strong unsuccessfully challenged McIntyre for the NXT Championship on the October 5 episode of NXT. Strong was pinned by Almas on the October 25 episode of NXT following interference from Zelina Vega.
Strong then entered a program with The Undisputed Era (Adam Cole, Bobby Fish, and Kyle O'Reilly). For weeks, the trio tried to recruit Strong to join the group in an attempt to overtake NXT. During a match between SAnitY and The Authors of Pain on the November 1 episode of NXT, The Undisputed Era interfered and caused the match to end in a no-contest. Strong entered the fray and pulled out an Undisputed Era armband, seemingly joining the group. However, Strong attacked the three, and cleared the ring alongside The Authors of Pain. General manager William Regal emerged on the ramp, and announced a WarGames match for NXT TakeOver: WarGames (originally known as TakeOver: Houston). Strong would team with The Authors of Pain against The Undisputed Era and SAnitY. At the event, Strong (who dressed in a similar attire to his teammates) and The Authors of Pain were unsuccessful in winning. On the December 20 episode of NXT, Strong was defeated by Lars Sullivan in the first round of an NXT Championship No. 1 Contender's Tournament.
On the January 30, 2018 episode of 205 Live, 205 Live General Manager Drake Maverick announced the 2018 WWE Cruiserweight Championship Tournament. Strong was later announced as a participant in the tournament, in which he would defeat Hideo Itami in the first round and Kalisto in the quarter-finals on the February 6 and February 27 episodes of 205 Live before being defeated by Cedric Alexander in the semi-finals on the March 13 episode of 205 Live.
At NXT TakeOver: New Orleans, during the triple threat match for the NXT Tag Team Championship and the Dusty Rhodes Tag Team Classic trophy, Strong turned on his partner Pete Dunne and joined the Undisputed Era, turning into a villain in the process for the first time in his WWE career. The next morning at WrestleMania Axxess, Strong teamed with O'Reilly to defend the NXT Tag Team Championship, making him one of the champions via the Freebird Rule. At the Greatest Royal Rumble, Strong competed in the namesake match, entering at #34 and eliminating Rhyno before being eliminated by Baron Corbin.
At NXT TakeOver: Chicago II, O'Reilly and Strong defeated Danny Burch and Oney Lorcan to retain the NXT Tag Team Championship. On day 2 of the 2018 WWE United Kingdom Championship Tournament, O'Reilly and Strong lost the NXT Tag Team Championship against Moustache Mountain (Tyler Bate & Trent Seven). However, they would regain the championships on the July 11, 2018, episode of NXT, after Bate throw the towel over an injured Seven. At NXT TakeOver: Brooklyn 4, O'Reilly and Strong defeated Moustache Mountain to retain the titles. All four members of the Undisputed Era competed in a WarGames match at NXT TakeOver: WarGames II against Ricochet, Pete Dunne, Rowe, and Hanson, in a losing effort. At NXT TakeOver: Phoenix on January 26, Strong and O'Reilly dropped the NXT Tag Team Championship to Rowe and Hanson, ending their reign at 219 days. At NXT TakeOver: New York, Strong interfered in Adam Cole's NXT Championship match against Johnny Gargano. Afterwards, Strong would begin a feud with Matt Riddle. At NXT TakeOver: XXV on June 1, Strong was defeated by Riddle. Following the loss, Strong began a feud with Velveteen Dream over the NXT North American Championship, eventually losing in a title match at NXT TakeOver: Toronto II, also involving Pete Dunne. On September 18 during the debut episode of NXT on the USA Network, Strong - with help from his Undisputed Era teammates - won the NXT North American Championship by defeating Velveteen Dream, giving him his first single title in WWE, and giving the Undisputed Era all male championships available in NXT. He would then, alongside the Undisputed Era, begin a feud against Tommaso Ciampa, Matt Riddle, and Keith Lee which would lead to a WarGames match at NXT TakeOver: WarGames, in which the Undipsuted Era lost to the team of Ciampa, Lee, Dominik Dijakovic, and Kevin Owens. The next night at Survivor Series, he defeated SmackDown's Intercontinental Champion Shinsuke Nakamura and Raw's United States Champion AJ Styles in an inter-brand triple threat match.
On the January 22, 2020 episode of NXT, Strong dropped the NXT North American Championship to Keith Lee in the main event, thereby ending the Undisputed Prophecy. Beginning in June 2020, Strong began a feud with Dexter Lumis, who came to Velveteen Dream's aid in May 2020 to help him in his war with the Undisputed Era. During that time, Dexter kidnapped Strong during NXT TakeOver: In Your House to keep him from interfering in Adam Cole's match with Dream. Though returned to his allies, Strong was heavily traumatized by the kidnapping and developed a deathly fear of Dexter as a result. His teammates attempted to curtail his sudden panic and fear by having him go to therapy. At NXT The Great American Bash, Strong lost to Dexter Lumis in a strap match.
Later on in the year, The Undisputed Era began a feud with Pat McAfee, Oney Lorcan, Danny Burch, and Pete Dunne, thus turning face in the process. This culminated at NXT TakeOver: WarGames in a WarGames match, with the Undisputed Era winning. At NXT TakeOver: Vengeance Day, after O'Reilly was defeated by Finn Balor, Adam Cole superkicked O'Reilly and Balor. On the February 24, 2021 episode of NXT, Adam Cole turned and double-crossed Strong as well. On the March 24, 2021 episode of NXT, Strong was approached by Cameron Grimes, who tried to propose a "business deal" with him. However, Strong rejected the offer by punching Grimes. On the March 31 episode of NXT, Strong was defeated by Cameron Grimes. Later on in the show, McKenzie Mitchell would attempt to interview him but Strong walked off and said he was "done". On the April 13 episode of NXT, Strong was seen waiting for General Manager William Regal and handed him an envelope saying that he was done.
Strong would make his return on June 22 episode of NXT, attacking Kushida, as the leader of The Diamond Mine stable along with Tyler Rust and Hideki Suzuki, with Malcolm Bivens as their manager. On the September 21 episode of NXT 2.0, Strong defeated Kushida to win the NXT Cruiserweight Championship. At NXT New Year's Evil on January 4, 2022, he lost the title to Carmelo Hayes, unifying both North American and Cruiserweight titles. Strong and the rest of Diamond Mine would slowly turn face at the start of 2022, when they entered a feud with Imperium. On the March 17, 2022 episode of NXT UK, Strong made his debut for the brand, defeating Wolfgang. In September 2022, Strong would begin a hiatus due to suffering an ankle injury. After not appearing on television for the next seven months, Strong was officially released on April 27, 2023.