In 2019, Omos made his in-ring debut for WWE during a July 18 NXT house show, defeating Ever-Rise in a two-on-one handicap match. He returned the following month during an August 24 house show, winning a 15-man battle royal. During October house shows, Omos was victorious in singles matches defeating competitors Cezar Bononi and Kona Reeves. Omos returned in 2020 during an NXT house show to team with Bronson Reed and defeat Aleksandar Jaksic and Tehuti Miles.
During the June 15, 2020 episode of Monday Night Raw, Omos debuted as a surprise member of Akira Tozawa's ninja faction. Appearing as the tallest member of the faction, Omos was referred to as the "Big Ninja" as he stood at ringside during team Tozawa's tag match against The Street Profits and The Viking Raiders. Big Ninja was also confronted by Big Show during the post-match brawl between the teams.
Between August and October, he served as the security guard for Shane McMahon's Raw Underground.
In October, he would begin to accompany AJ Styles to the ring as his "associate" when Styles returned to the Raw brand. At the 2020 Survivor Series event, he was introduced with a new ring name, Omos. At TLC: Tables, Ladders and Chairs, Omos was involved in the WWE Championship TLC match, preventing The Miz from reaching the title and dropping him onto a table placed outside the ring before chasing John Morrison to the back. During the 2021 Royal Rumble match, Omos involved himself by preventing AJ Styles from being eliminated on a few occasions. Omos also eliminated Big E and Rey Mysterio despite not being in the match. He would also go on to help Styles enter the Elimination Chamber match early before being ejected by WWE official Adam Pearce. On the March 15, 2021 episode of Raw, Omos announced that he would be making his in-ring debut at WrestleMania 37 alongside Styles against The New Day for the WWE Raw Tag Team Championships. On April 10, 2021, at WrestleMania 37, Omos and Styles defeated The New Day for the Raw Tag Team Championships, Omos' first championship in WWE. On the July 19 episode of Raw, Styles, Omos, and John Morrison lost to Riddle and the Viking Raiders. During the match, Riddle sprayed Omos with water, and The Miz, who was at ringside, was accused of spraying him. Omos subsequently went to attack Miz, and Morrison, who was trying to stop Omos from attacking him, was thrown back to the ring by Omos, which caused the Viking Warriors to perform their finisher on Morrison and win the match. At SummerSlam, Omos and Styles lost the Raw Tag Team Championships to RK-Bro (Randy Orton and Riddle). At Extreme Rules, Omos and Styles teamed with Bobby Lashley to take on The New Day in a six-man tag team match, in which Styles, Omos and Lashley lost. After this, it was announced that Styles and Omos would face RK-Bro in a rematch for the tag titles at Crown Jewel. At the event, they failed to regain the titles.
At Survivor Series on November 21, Omos participated in a twenty-five man dual-branded battle royal to commemorate the twenty-fifth anniversary of The Rock's debut. Omos had the most eliminations at twelve, and won the match by last eliminating Ricochet. After weeks of tension between the two, on the December 20, 2021 episode of Raw, Omos refused to tag into their match against Rey Mysterio and Dominik Mysterio, ultimately costing them the match. A fight then broke out between the two, effectively ending their alliance.
On the January 3, 2022 episode of Raw, a week after splitting up from Styles, a match was set up between the two, where Omos defeated Styles. On January 29, at the Royal Rumble, Omos entered the namesake match for the first time in his career at number eleven, where he eliminated Montez Ford, Angelo Dawkins, and Damian Priest before he was eliminated by Styles, Austin Theory, Chad Gable, Dominik Mysterio, Ricochet, and Ridge Holland. On night two of WrestleMania 38, he faced Bobby Lashley in a losing effort, marking his first loss in WWE. On the April 4 episode of Raw, Omos and MVP attacked Bobby Lashley, thus forming an alliance between the two. He defeated Lashley at WrestleMania Backlash with MVP’s help, but lost to him in a steel cage match on the May 16 episode of Raw. At Hell in a Cell, Omos and MVP lost to Lashley in a two-on-one handicap match, ending their feud.
On June 20, Omos would qualify for the men’s Money in the Bank ladder match after defeating Riddle. At the event, he would fail at winning the match after being thrown through a table by all the other competitors. On the October 14 episode of SmackDown, Omos confronted Braun Strowman, starting a feud between the two. At Crown Jewel on November 5, Omos lost to Strowman. At the Royal Rumble on January 28, 2023, Omos entered the Royal Rumble match at number twenty-four, but was eliminated by Strowman. On March 20, on Monday Night Raw, Omos defeated Mustafa Ali in two minutes. After calling out Brock Lesnar for a match at WrestleMania 39, Lesnar would eventually accept. At the event, Lesnar defeated Omos. He would then lose to Seth Rollins at Backlash.
Omos would return after a short hiatus as the final entry in the SummerSlam battle royal on August 5, being introduced by MVP, but was unsuccessful in winning the match after being eliminated by eight individuals. In the 2024 Royal Rumble match, Omos entered at number twenty-one before being eliminated by Bron Breakker.