He is a member of the Chaos stable and also makes appearances for Consejo Mundial de Lucha Libre (CMLL), as well as Major League Wrestling (MLW).

In the United States, he is known for his work with Ring of Honor as a member of No Remorse Corps, and was one of the featured wrestlers for Lucha Libre USA.

[4] Romero made his debut in Pro Wrestling Noah on March 4, 2007, versus Mushiking Terry, casting into doubt the future of the Black Tiger persona.

On September 12, Romero became CMLL's first-ever World Super Lightweight Champion after defeating Volador Jr. in a tournament final.

[16] The five-day-long tournament ended on November 13, with Romero and Richards winning their block and advancing to the finals, where they were defeated by their Chaos team mates Jado and Gedo.

[17] On May 3, 2011, Romero and Richards unsuccessfully challenged Prince Devitt and Ryusuke Taguchi for the IWGP Junior Heavyweight Tag Team Championship.

[18] On October 10, 2011, at Destruction '11, Romero and Richards defeated Devitt and Taguchi in a rematch to win the IWGP Junior Heavyweight Tag Team Championship for the first time.

[19] Romero and Richards made their first successful title defense on November 12 at Power Struggle, defeating the team of Kushida and Tiger Mask.

[21] On January 4, 2012, at Wrestle Kingdom VI in Tokyo Dome, Romero and Richards lost the IWGP Junior Heavyweight Tag Team Championship back to Devitt and Taguchi.

[27] Romero and Koslov made their first successful title defense on August 26 at a Sacramento Wrestling Federation (SWF) event in Gridley, California, defeating the team of A.J.

[28][29] Forever Hooligans made their second successful title defense on October 8 at King of Pro-Wrestling, defeating the Time Splitters (Alex Shelley and Kushida).

[30] On October 21, Forever Hooligans entered the 2012 Super Jr. Tag Tournament, defeating Jyushin Thunder Liger and Tiger Mask in their first round match.

[38] On September 20 at Death Before Dishonor XI, the Forever Hooligans defeated the American Wolves in a rematch to retain the IWGP Junior Heavyweight Tag Team Championship.

[39] For the first half of 2014, Forever Hooligans received several new shots at the NJPW Junior Heavyweight Tag Team Championship, held by The Young Bucks (Matt and Nick Jackson), but were defeated each time,[40][41] including in a three-way match, also involving the Time Splitters, on May 10 at Global Wars, a special event co-produced by NJPW and ROH in Toronto.

[49] On April 10 at Invasion Attack 2016, Roppongi Vice defeated Matt Sydal and Ricochet to win the IWGP Junior Heavyweight Tag Team Championship for the second time.

[51] On November 5 at Power Struggle, Roppongi Vice defeated A. C. H. and Taiji Ishimori in the finals to win the 2016 Super Jr. Tag Tournament.

[52] On January 4, 2017, at Wrestle Kingdom 11 in Tokyo Dome, Roppongi Vice defeated The Young Bucks to win the IWGP Junior Heavyweight Tag Team Championship for their third time together.

[58] Roppongi Vice's farewell match took place on September 16 at Destruction in Hiroshima, where they defeated Bullet Club's Chase Owens and Yujiro Takahashi.

[68] On the February 12, 2024 edition of Wrestling Observer, journalist Dave Meltzer reported that, Romero joined AEW's front office.

[69] At Bound for Glory on October 23, 2021, Romero made an unannounced appearance as a participant in the Call Your Shot Gauntlet match, which he failed to win as he was eliminated by Rohit Raju.