Moss signed a developmental contract with WWE in early 2014 and began training at the WWE Performance Center. He made his professional wrestling debut on December 18 at an NXT live event in Tampa, Florida under the ring name Digg Rawlis. He made his televised debut on the May 27, 2015, episode of NXT, working as an enhancement talent alongside Elias Samson in a losing effort against Blake and Murphy. Rawlis made further occasional televised appearances as an enhancement talent during 2015, losing to The Hype Bros and Samoa Joe. In August 2015 he adopted the new ring name Riddick Moss.
In October 2016, Moss began teaming with Tino Sabbatelli, (calling themselves the God Gifted Athletes) with the two competing in the 2016 Dusty Rhodes Tag Team Classic, where they were defeated in the first round by TM61 on the October 12 episode of NXT. Moss made a further appearance on the January 4, 2017, episode of NXT, again teaming with Sabbatelli in a defeat to The Revival (Dash Wilder and Scott Dawson). Moss and Sabbatelli made another appearance on the May 10 episode of NXT, losing to #DIY (Johnny Gargano and Tommaso Ciampa). The duo had their first televised victory on the October 25 episode of NXT, defeating the team of Oney Lorcan and Danny Burch. In early 2018, Moss and Sabbatelli entered the Dusty Rhodes Tag Team Classic, losing to Sanity in the first round. On April 25, during a match with Heavy Machinery, Sabbatelli ditched Moss, thus ending the team. In May 2018, he tore his Achilles tendon and would require several months to recuperate. He would make his return from injury on a November 30, 2018 live event, losing to Matt Riddle after a surprise appearance. In March 2019, he started being managed by Robert Strauss at NXT live events. On the May 8, 2019 episode of NXT, Moss competed in his first televised match since his injury in a loss to Raul Mendoza.
On the January 27, 2020 episode of Monday Night Raw, Moss made his Raw debut, accompanying Mojo Rawley to the ring for his 24/7 Championship match with No Way Jose. Moss was billed as Rawley's 'offensive lineman'. While Rawley would win the initial match, Rawley would lose to R-Truth moments later; however Riddick would assist Rawley in regaining the championship just seconds later. On the February 10 episode of Raw, after losing a tag team match to the Street Profits, Moss turned on Rawley and pinned him to win the 24/7 Championship. On March 22, Moss lost the title to R-Truth while out for a jog, ending his reign at forty-one days.
On the August 10 episode of Raw, Moss made his Raw return in a Raw Underground segment, an underground fight club hosted by Shane McMahon, where he defeated Cal Bloom by knockout. Moss would dominate most of his matches on Raw Underground before suffering a torn ACL in September 2020. After being out of action for an entire year, Moss returned from injury by defeating Odyssey Jones in a dark match before the September 17, 2021 episode of SmackDown. The following week, Moss made his televised return by aligning with Happy Corbin and attacking Kevin Owens. The following week, he was re-introduced as Corbin’s associate, Madcap Moss. Later, Corbin would defeat Owens in a singles match, and the two started to feud with the Shinsuke Nakamura and Rick Boogs, with Corbin defeating Nakamura in a championship contenders match, and Moss and Corbin defeating Nakamura and Boogs in a street fight. Later, the two were defeated by The Viking Raiders by count out.
He and Corbin then entered into a feud with Drew McIntyre, after they mocked McIntyre for not being in the number one contender battle royal match for the Universal Championship. In the following weeks, they continued to mock McIntyre and make jokes at his expense. This led to a match between the two at WWE Day 1, with Moss losing. Madcap Moss entered the Royal Rumble match at the namesake event, his first Royal Rumble match. He entered at number 16 and lasted four minutes and twenty-four seconds, scoring two eliminations. Moss was eliminated by Drew McIntyre, continuing their feud. He fought McIntyre in a Falls Count Anywhere match at Elimination Chamber, in a losing effort.
On the April 1, 2022 edition SmackDown, Moss won the 2022 André the Giant Memorial Battle Royal, last eliminating Finn Balor. At WrestleMania 38, on night one, Moss accompanied Corbin to the ring for his match against McIntyre. Corbin lost the match, and when Moss tried to attack McIntyre after the match, the latter swung a sword at Moss, which he narrowly avoided, at the expense of the ring ropes. On the April 8 edition of SmackDown, Happy Corbin blamed Madcap Moss for his loss at WrestleMania 38 against McIntyre. Corbin and Madcap then brawled with each other, thus turning face for the first time since 2015 and ending the alliance between the two. On the April 15 edition of SmackDown, Moss would return to singles competition by defeating Humberto, one half of Los Lotharios. On the April 29 edition of SmackDown, Moss would interrupt Happy Talk after he disguised himself a cameraman, thus attacking him and reclaiming the Andre the Giant Memorial Battle Royal trophy that Corbin had earlier absconded. On the May 6 edition of SmackDown, Moss would interrupt Happy Talk once again, making jokes about Happy Corbin which would lead to Corbin leaving the ring. At WrestleMania Backlash, Moss would defeated Corbin. On the May 13 episode of SmackDown, during an interview, Happy Corbin would attack Moss from behind and injure his neck with the André the Giant Memorial Battle Royal trophy, which left Moss unconscious and had to be stretchered out of the arena. Moss would make his return on the June 3 edition of SmackDown, with a more serious persona, new entrance music and ring attire, and challenged Happy Corbin to a match. WWE official Adam Pearce made the match official, and Moss disqualified himself by hitting Corbin with a chair. It was later announced that Moss would face off in a No Holds Barred match at Hell in a Cell against Corbin, where Moss was victorious. On the June 17 episode of SmackDown, Moss defeated Corbin for a third time in a Last Laugh match to end their feud.
On July 4, Moss would compete in the Money in the Bank ladder match after qualifying for a final spot on the July 3 edition of SmackDown. However, he would fail to win the match as Theory retrieved the briefcase. On the August 19 episode of SmackDown, Moss competed in a fatal five-way match to determine the number one contender for the Intercontinental Championship, which was won by Sheamus. On the Clash at the Castle pre-show on September 3, Moss and The Street Profits (Angelo Dawkins and Montez Ford) defeated Alpha Academy (Chad Gable and Otis) and Austin Theory. On the September 16 episode of SmackDown, Moss challenged Solo Sikoa for the NXT North American Championship in a losing effort. Towards the end of 2022, Moss would begin an on-screen relationship with the recently returning Emma. On the February 10 episode of SmackDown, Moss defeated Karrion Kross, Santos Escobar, and Rey Mysterio in a fatal four-way match to become the number one contender for Gunther's Intercontinental Championship. The following week, Moss failed to win the title. In April, Moss' ringname was reverted back to Riddick Moss.
Moss was drafted to the Raw brand in the 2023 WWE Draft. On September 21, Moss was released from his WWE contract.