On February 24, 2011, WWE held a press conference in Mexico City to introduce Sin Cara. On March 25, Sin Cara made his WWE debut at a Raw live event in Champaign, Illinois, defeating Primo in a singles match. On the April 4 episode of Raw, Sin Cara debuted, saving Daniel Bryan from an attack by WWE United States Champion Sheamus, and establishing himself as a face. On that week's SmackDown, Sin Cara similarly appeared, this time attacking Jack Swagger and cementing his face status. Sin Cara made his televised in-ring debut on April 11, defeating Primo. In the 2011 WWE draft, Sin Cara was drafted to SmackDown, making his first appearance as part of the roster on the April 29 episode with a win over Jack Swagger. Sin Cara then started a storyline feud with Chavo Guerrero, who began guest commentating his matches and, much to Sin Cara's dismay, even helped him win matches by interfering on his behalf. Sin Cara made his pay-per-view debut on May 22 at Over the Limit, defeating Chavo Guerrero. Sin Cara's undefeated streak came to an end on the July 1 episode of SmackDown, when he was defeated by Christian.
On July 17, Sin Cara participated in the SmackDown Money in the Bank ladder match at the eponymous pay-per-view but failed to earn a World Heavyweight Championship match after being taken out of the match with a storyline injury. The following day, WWE announced that it had suspended Sin Cara for 30 days for his first violation of its Wellness program.
The Sin Cara character returned on the August 12 episode of SmackDown, defeating Tyson Kidd; however, with the original Sin Cara still serving his suspension, for this appearance Sin Cara was portrayed by Hunico. After another week of Hunico portraying Sin Cara, the original Sin Cara returned under the mask on August 20 at a live event in Tacoma, Washington. During the original Sin Cara's time away from WWE, the Sin Cara character seemingly turned heel by attacking Daniel Bryan.
At the tapings of the September 16 episode of SmackDown, the original Sin Cara returned, confronting the impostor version of the character. On Raw's September 19 episode, the original Sin Cara was booked to face Cody Rhodes, but was attacked by the impostor Sin Cara prior to the match starting. On the September 23 episode of SmackDown, the impostor Sin Cara attacked the original version during his match with Daniel Bryan, then took his place in the match and pinned Bryan for the win. The following week, the impostor revealed new black attire to distinguish himself from the original version, while also explaining that he was going to steal the Sin Cara identity, leading to a match between the two Sin Caras at Hell in a Cell. To further distinguish the two characters, WWE began referring to the original as Sin Cara "Azul" (Blue) and the impostor as Sin Cara "Negro" (Black). At the pay-per-view on October 2, Sin Cara Azul defeated Sin Cara Negro in a singles match. The rivalry culminated in a mask versus mask match at the October 16 taping of SmackDown in Mexico City, where Sin Cara Azul was victorious, unmasking Sin Cara Negro after the match. Afterward, the unmasked Sin Cara Negro changed his ring name to Hunico, aligned himself with Camacho and continued his rivalry with Sin Cara. On November 20, at Survivor Series, Sin Cara and Hunico were on opposite sides of a ten-man tag match. Sin Cara was eliminated after he suffered a legitimate patellar tendon rupture while diving out of the ring. He underwent surgery and was unable to wrestle for over six months.
Sin Cara returned on May 19, 2012, at a live event in Florence, South Carolina, defeating Hunico in the opening match. On the June 1 episode of SmackDown, Sin Cara returned to television in new red and white attire, defeating Heath Slater. On the July 9 episode of Raw, Sin Cara defeated Heath Slater to qualify for the World Heavyweight Championship Money in the Bank ladder match at the Money in the Bank pay-per-view, but was unsuccessful in the match itself, which was won by Dolph Ziggler.
In August, Sin Cara rekindled a feud with Cody Rhodes, who claimed that he was wearing a mask to cover his ugly face. Sin Cara scored pinfall wins over Rhodes in consecutive matches on SmackDown and Raw, both times taking advantage of Rhodes trying to remove his mask. He then also saved fellow masked wrestler Rey Mysterio from being unmasked by Rhodes and afterward teamed up with Mysterio to put one of his masks on Rhodes. After defeating WWE Intercontinental Champion The Miz in a non-title match, Sin Cara was granted an opportunity to challenge for the title at Night of Champions in a four-way match, which also included Rhodes and Mysterio. The storyline between Sin Cara, Rhodes and Rey Mysterio was furthered as The Miz retain the championship. The following day on Raw, Sin Cara and Mysterio teamed up to defeat Epico and Primo in a tag team match. Sin Cara and Mysterio entered a tournament to determine the number one contenders to the WWE Tag Team Championship, defeating Primo & Epico and The Prime Time Players (Titus O'Neil and Darren Young) to advance to the final. Sin Cara and Mysterio lost the final of the tournament to Team Rhodes Scholars (Cody Rhodes and Damien Sandow) on the October 22 episode of Raw. At Survivor Series on November 18, Sin Cara and Mysterio were victorious in a ten-man elimination tag team match alongside Brodus Clay, Justin Gabriel, and Tyson Kidd against the Prime Time Players, Epico, Primo, and Tensai. On December 16 at TLC: Tables, Ladders and Chairs, Sin Cara and Mysterio were defeated by Team Rhodes Scholars in a number one contenders tables match for the WWE Tag Team Championship. Two days later on SmackDown, Sin Cara suffered a legitimate knee injury and was written off television following an attack by The Shield.
Sin Cara returned on January 27, 2013, at the Royal Rumble, entering the Royal Rumble at number twenty-nine, but was eliminated by Ryback. On the following episode of SmackDown, Sin Cara and Rey Mysterio defeated WWE Tag Team Champions Team Hell No (Daniel Bryan and Kane) in a non-title match. Sin Cara returned to television on the May 15 episode of Main Event, defeating Intercontinental Champion Wade Barrett in a non-title match. During the August 19 episode of Raw, Sin Cara dislocated his ring finger during a match with Alberto Del Rio. The original Sin Cara's final match was against Alberto Del Rio at a show in Monterrey, Mexico on October 19.
On March 26, 2014, he was released by WWE.