On February 24, 2021, Williams signed a developmental contract with WWE and was assigned to the WWE Performance Center and subsequently the NXT brand. Later that year, he made his first appearance on the September 14 episode of NXT as the bodyguard of Carmelo Hayes. Williams made his in-ring debut on the October 5 episode of NXT, teaming with Hayes in a fatal four-way elimination tag team match for the NXT Tag Team Championship, where they lost to MSK (Nash Carter and Wes Lee).
Throughout 2022 and 2023, Williams accompanied Hayes in most matches. On the August 1, 2023 episode of NXT, Williams told Hayes that they needed to part ways so he could achieve his own accomplishments, amicably breaking up the Trick Melo Gang. On the September 26 episode of NXT, Williams became the number one contender to the NXT North American Championship by defeating Axiom, Dragon Lee and Tyler Bate in a fatal four-way match. A few days later at NXT No Mercy, Williams won the title by defeating The Judgment Day's "Dirty" Dominik Mysterio. However, just three days later on NXT, Williams lost the title back to Mysterio after interference from Mysterio's Judgment Day stablemates Finn Bálor, Damian Priest, and Rhea Ripley, as well as their associate JD McDonagh, marking it the shortest reign in the title's history.
On the October 17 episode of NXT, Williams was slotted into the triple threat match between Hayes, Dijak and Baron Corbin to make it a fatal four-way match for an NXT Championship opportunity against Ilja Dragunov at NXT Halloween Havoc; this announcement caused a rift between Williams and Hayes. Before the match started, Williams was found attacked backstage and had to be taken to a hospital. Hayes went on to defeat Dijak and Corbin for the title opportunity. At NXT Halloween Havoc, during night two, Williams returned during the NXT Championship match and cost Hayes the title, staring him down after the match. On the November 14 episode of NXT, Williams defeated Joe Coffey to qualify for the Iron Suvivor Challenge at NXT Deadline. At NXT Deadline on December 9, Williams won the men's Iron Survivor Challenge to earn an NXT Championship match against Dragunov at NXT New Year's Evil. At New Year's Evil on January 2, 2024, it was announced that Dragunov was not medically cleared to compete. Williams instead was put in a match against Grayson Waller with his Iron Survivor Challenge title match on the line by Hayes. Williams went on to defeat Waller after interference from Kevin Owens. On the January 16 episode of NXT, Dragunov returned from his injury and informed Williams that their title match would take place at NXT Vengeance Day. On the same edition of NXT, Williams and Hayes defeated Edris Enofé and Malik Blade in the first round of the Dusty Rhodes Tag Team Classic. Williams made his SmackDown debut on January 26, saving Hayes from a beatdown by A-Town Down Under (Grayson Waller and Austin Theory). On the January 30 episode of NXT, Williams and Hayes defeated Latino World Order's Joaquin Wilde and Cruz Del Toro to advance to the finals of the Dusty Rhodes Tag Team Classic.
At NXT Vengeance Day on February 4, Williams and Hayes lost to Baron Corbin and Bron Breakker in the finals of the Dusty Rhodes Tag Team Classic. Later that night, Williams failed to win the NXT Championship from Ilja Dragunov. After the match, Hayes attacked Williams with a steel chair, ending their partnership. On the following episode of NXT, Hayes revealed that he was the one who attacked Williams back in October 2023. At NXT Roadblock on March 5, Williams' entrance music was used by The Family's Tony D'Angelo to distract Hayes during their match to determine the number one contender for the NXT Championship at NXT Stand and Deliver. After D'Angelo defeated Hayes, Williams made his return and attacked Hayes. The following week on NXT, Williams challenged Hayes to a match at NXT Stand and Deliver, which was made official a few days later. Williams went on to defeat Hayes at the event on April 6. On the following episode of NXT, Williams called out Dragunov to challenge him for the NXT Championship. Dragunov agreed to a title match at Spring Breakin' on the condition that Williams would leave NXT if he lost, which Williams accepted. Hayes then attacked Williams from behind and told him that they would face each other the following week in a steel cage match, which Williams would win, ending the feud. During week one of Spring Breakin', Williams defeated Dragunov to capture the NXT Championship for the first time in his career.
Following the win, The Meta-Four's Lash Legend would appear and reveal that the stable had a secret that would derail his title reign. On the May 7 episode of NXT during Supernova Sessions, Noam Dar said that in a match between them which was won by Williams, Dar's leg was under the ropes, which should have broken the pinfall, and called Williams a fraud. Dar proceeded to attack Williams shortly after Legend revealed that she was having a relationship with Williams. On the following week, Dar was found attacked by an unknown assailant. Later that night, Williams assisted Je'Von Evans in defeating Oro Mensah, and a partnership between Williams and Evans was formed. On the May 28 episode of NXT, Williams and Evans defeated Gallus' Joe Coffey and Mark Coffey in a tag team match. After the match, Williams was attacked by a debuting Ethan Page, who revealed himself as Dar's attacker. At NXT Battleground on June 9, Williams successfully defended the NXT Championship against Page. At NXT Heatwave on July 7, Williams lost the title to Page in a fatal four-way match also involving Je'Von Evans and Shawn Spears, the former of whom Page pinned, ending his reign at 75 days.