On April 18, 2019, it was announced that Garza signed a contract with WWE and begun working at their Performance Center. In June, it was announced that Garza would compete in a tournament named the NXT Breakout Tournament, where he made his debut on the June 26 episode of NXT, defeating Joaquin Wilde in the first round of the tournament. On the July 24 episode, Garza lost to Jordan Myles in the semifinals. On the August 20 edition of 205 Live, Garza was chosen to be on Drew Gulak's team in the "Captain's Challenge" ten-man tag match, where his team was defeated by Oney Lorcan's team. On November 6, episode of NXT, Garza picked up a victory against Tony Nese for the number one contender of NXT Cruiserweight Championship to face Lio Rush. He received the title shot the following week, where he was unsuccessful in winning the title. On the December 11 episode of NXT, Garza defeated Rush to win the Cruiserweight Championship, his first title in the WWE. On January 25, 2020, at Worlds Collide, Garza lost the title to Jordan Devlin in a fatal four way match, also involving Isaiah "Swerve" Scott and Travis Banks.
On the February 3 episode of Raw, Garza made his main roster debut as a heel and the newest associate of Zelina Vega, and opposed his real-life cousin Humberto Carrillo, and viciously assaulted his cousin until the latter was rescued by Rey Mysterio. Garza subsequently faced Mysterio in his Raw in-ring debut, where Garza lost via disqualification after DDT-ing Mysterio on the concrete floor. Garza would make his WrestleMania debut at WrestleMania 36, where he teamed with Zelina Vega's other new prospect, Austin Theory, in a loss to The Street Profits in a Raw Tag Team Championship match. On the April 13 episode of Raw, Garza, Andrade and Theory attacked Akira Tozawa and all three posed together, confirming their status as a faction. However on the May 18 episode of Raw, they kicked Theory out of their faction for accidentally costing them their match against Kevin Owens and Apollo Crews. The following week on Raw, Garza defeated Kevin Owens in an upset victory. On the June 8 episode of Raw, Garza competed in a triple threat match against Andrade and Owens for an opportunity at the United States Championship at Backlash, but was pinned by Andrade. During the match, Andrade and Garza accidentally knocked out Vega after getting in to an argument. At Backlash, Garza attempted to help Andrade defeat Crews but was stunned by Owens at ringside which led to Crews retaining the title. The following night on Raw, Garza lost to Owens after Andrade's interference on Garza's behalf backfired. On the June 22 episode of Raw, Garza and Andrade attacked the Street Profits after their match with The Viking Raiders, making their intentions known for the Raw Tag Team Titles. Over the next few weeks, Garza and Andrade would feud with The Viking Raiders, defeating them in a tag team elimination match, but struggled to get on the same page as a tag team. Andrade and Garza would start to coexist as a tag team as they defeated The Viking Raiders and Cedric Alexander and Ricochet to earn a Raw Tag Team Title shot against Street Profits at SummerSlam, which they would lose. At the event, they were defeated by the Street Profits after a miscommunication between Garza and Andrade. On the September 14 episode of Raw, Vega ended her association with Garza and Andrade, having had enough of them constantly arguing and fighting with each other. The following week on Raw, Garza and Andrade (without Vega) defeated Seth Rollins and Murphy and Dominik Mysterio and Humberto Carrillo to once again become number one contenders for the Raw Tag Team Titles against the Street Profits at Clash of Champions. At the event, they were once again unsuccessful at capturing the titles as Garza suffered a legitimate knee injury during the match.
Garza returned on the October 12 episode of Raw, defeating Andrade, thus officially splitting up the team. On December 31, Garza won his first 24/7 Championship from R-Truth during a New Year's Eve party hosted on WWE's social media. However on the January 4, 2021 episode of Raw, The Boogeyman appeared and scared him, thus allowing him to be pinned by R-Truth to regain the 24/7 Championship title. On the May 3 edition of Raw, Drew Gulak confronted Garza, which lead to a match, which Garza won. Following the win, Garza shoved a rose down Gulak's pants and then kicked it. In the following months, Garza would occasionally be seen backstage pursuing the 24/7 Championship. On the September 20 episode of Raw, Garza formed a tag team with his cousin Humberto Carrillo, defeating Mansoor and Mustafa Ali. As part of the 2021 Draft, both Garza and Carrillo were drafted to the SmackDown brand. On the November 5 episode of SmackDown, the team was officially dubbed Los Lotharios, with both Garza and Carrillo shortening their ring names, being billed as Angel and Humberto.
As part of the 2023 WWE Draft, Angel, along with Humberto, was drafted to the Raw brand. However, before they would make their first appearance on the red brand, Los Lotharios returned to television on the June 13, 2023 episode of NXT, attacking Axiom and Scrypts after their win against Dabba-Kato. Angel would then revert his ring name back to Angel Garza. Angel, with Humberto, returned to the main roster on the December 22 episode of SmackDown, aligning with Santos Escobar.