In November 2016, Holland attended a tryout for WWE. In May 2018, it was announced that Holland had signed with WWE. On the August 29, 2018 edition of NXT, Holland made his televised debut, losing to Keith Lee. On November 21, 2019, he made his television debut for the NXT UK brand, defeating Oliver Carter. On January 30, 2020, on NXT UK, he defeated Tyson T-Bone.
On August 5, 2020, Holland made his official NXT television debut, competing in a triple threat match against Damian Priest and Oney Lorcan for an opportunity at the NXT North American Championship, which Priest would win after pinning Lorcan. NXT General Manager William Regal later announced that Dexter Lumis had pulled out of the ladder match at NXT TakeOver: XXX due to an ankle injury, and since Holland was not pinned or submitted in his qualifying match as a result of Lorcan being pinned, he was given the chance to face Johnny Gargano on the August 19 episode of NXT, with the winner being added to the ladder match; he lost due to interference from Gargano's manager and wife Candice LeRae. At NXT TakeOver: 31 on October 4, 2020, after the main event pitting Kyle O'Reilly against Finn Bálor for the NXT Championship, Holland appeared at ringside carrying O'Reilly's unconscious Undisputed Era teammate Adam Cole over his shoulders, having apparently attacked Cole; he then dropped Cole over the barricade in front of Bálor and O'Reilly before leaving. On the October 7 episode of NXT, Holland brawled with Oney Lorcan and Danny Burch after defeating Burch in a match. As he caught Lorcan leaping over the top rope to deliver a cross-body, Holland's legs gave out from under him, and he had to be stretchered out of the arena, reportedly suffering an ankle dislocation and fracture in his left leg and a knee patellar dislocation and patellar tendon rupture in his right leg.
After a nine month absence due to injury, Holland returned on the July 27, 2021 episode of NXT, assisting Oney Lorcan and Pete Dunne in defeating Tommaso Ciampa and Timothy Thatcher and subsequently beat both men down post-match, teasing an alliance between the three.
On the October 4 episode of Raw, Holland was drafted to the SmackDown brand as part of the 2021 WWE Draft. On the November 5 episode of SmackDown, during a backstage interview, Holland referred to Sheamus as his idol. On the November 19 episode of SmackDown, Holland helped Sheamus defeat Cesaro, Ricochet, and Jinder Mahal in a four-way match, starting an alliance between the two. Holland made his in-ring debut the following week on SmackDown, where he lost to Cesaro. At WWE Day 1, Holland would team with Sheamus to defeat Cesaro and Ricochet, however, during the match, Holland would suffer a broken nose and would be removed mid-match. At the Royal Rumble, Holland participated in the namesake match, entering at number five, but was eliminated by AJ Styles. On night two of WrestleMania 38, he teamed with Sheamus to defeat The New Day, with Butch in their corner. At Clash at the Castle on September 3, Holland managed Sheamus against Gunther in an Intercontinental Championship match; though Sheamus was unsuccessful, he received a standing ovation from the Cardiff crowd, effectively turning Holland and the Brawling Brutes face in the process. On the September 16 episode of SmackDown, Butch and Holland won a fatal four-way tag team match to become the number one contenders for the Undisputed WWE Tag Team Championship. The following week, they faced the champions The Usos for the titles in a losing effort after interference from Imperium. Holland and Butch also appeared on the October 4 episode of NXT to challenge Pretty Deadly (Elton Prince and Kit Wilson) for the NXT Tag Team Championship, but lost due to Imperium's interference. Four days later at Extreme Rules, the Brawling Brutes defeated Imperium in a six-man tag team Good Old Fashioned Donnybrook match. On November 5 at Crown Jewel, Holland and Butch once again failed to win the Undisputed WWE Tag Team Championship from the Usos. Three weeks later at Survivor Series WarGames on November 26, The Brawling Brutes alongside Drew McIntyre and Kevin Owens lost to The Bloodline in a WarGames match.
On the December 19, 2023 episode of NXT, Holland challenged NXT Champion Ilja Dragunov to a title match, which Dragunov accepted. During the match, Holland dropped Dragunov on his head, which caused him to seemingly injure his neck and be stretchered off. This led to a storyline where, on the March 26, 2024 episode of NXT, Holland announced he would be going on an indefinite hiatus from in-ring competition. On April 6 however, Holland appeared on the pre-show of NXT Stand and Deliver to attack Joe Gacy with a steel chair as Gacy was making his entrance for his match against Shawn Spears, seemingly turning heel for the first time since 2022.
On the May 7 episode of NXT, Chase University's Thea Hail thanked Holland for comforting her at Spring Breakin'. Later that night, Duke Hudson lost to Lexis King after Holland attempted to assist Hudson but inadvertently cost him the match. The following week, Holland challenged The O.C. (Luke Gallows and Karl Anderson) to a tag team match when The O.C. mocked Holland for leaving the main roster to NXT. Andre Chase offered Riley Osborne to be Holland's tag team partner to Osborne's dissatisfaction. The O.C. won the match after another mishap from Holland. On the May 21 episode of NXT, Fallon Henley defeated Hail to qualify for a spot at the six-woman ladder match to crown the inaugural NXT Women's North American Championship at NXT Battleground. Backstage, Osborne got into an argument with Holland for costing Hail the match, to which Chase proposed that both men settle their differences in the ring where Holland defeated Osborne. After the match, Osborne still did not approve of Chase U working with Holland, with Hudson agreeing with Osborne. On the June 4 episode of NXT, Osborne and Hudson refused to walk out with Holland for Hail's match against Jazmyn Nyx. Halfway through the match, Osborne and Hudson showed up to ringside to Hail's surprise, to which Nyx used as an advantage to defeat Hail. On the June 18 episode of NXT, Holland was accepted as a member of Chase U. Holland entered into the 25-man battle royal for a NXT Championship match at NXT Heatwave, but he was eliminated. Later that night, Holland assisted Chase and Hudson to defeat The O.C. in a tag team match by giving Hudson leverage from outside the ring as Hudson pinned Anderson. After Andre Chase and Duke Hudson lost an NXT Tag Team Championship match at Heatwave on July 7, Holland secured a rematch for the titles, but Chase decided to team up with Holland. On the August 13 episode of NXT, Chase and Holland defeated Nathan Frazer and Axiom to become the new NXT Tag Team Champions, marking Holland's first championship win in WWE. On September 1 at NXT No Mercy, Chase and Holland lost the titles back to Frazer and Axiom, ending their reign at nineteen days. After the match, Holland viciously attacked Chase, defecting from Chase U and reverting back to a heel. After his defection, Hudson vowed to take down Chase U. On the September 10 episode of NXT, Holland defeated Hudson and took out Hudson with the barricade after the match. Two weeks later, Holland defeated Osborne, but failed to take him out. At NXT Halloween Havoc on October 27, Holland defeated a returning Chase in an Ambulance match. Later that night, Holland attacked Trick Williams after his successful NXT Championship defense against Ethan Page. Bubba Ray Dudley, who had a confrontation with Holland earlier that night, ran into the ring to save Williams from Holland and Page. On the November 19 episode of NXT, Holland faced Chase to earn a shot at the NXT Championship and with the future of Chase U on the line. Holland defeated Chase to earn a title shot against Williams at NXT Deadline and caused Chase U to be disbanded. At the event on December 7, Holland failed to win the title from Williams.