Adopting her Stardom gimmick of the "Genius of The Sky", Shirai made her WWE debut at the 2018 Mae Young Classic tournament, where she lost in the finals to Toni Storm.

[29][30][31][32] On April 29, the Shirai sisters won their first championship by defeating Moeka Haruhi and Tomoka Nakagawa in a tournament final to become the first TLW (Totally Lethal Wrestling) World Young Women's Tag Team Champions.

[42] On June 19, 2010, the Shirai sisters formed the Triple Tails stable with fellow freelancer Kana, defeating Ayumi Kurihara, Hikaru Shida and Yoshiko Tamura in their first match together at a NEO Japan Ladies Pro Wrestling event.

[46] Triple Tails returned to its winning ways on August 29, defeating Asami Kawasaki, Hikaru Shida and Nagisa Nozaki in a six-woman tag team match.

[47] On December 19, Triple Tails made its debut as a unit for Pro Wrestling Wave, defeating Cherry, Gami and Tomoka Nakagawa in a six-woman tag team main event.

[48] On January 29, 2011, the Shirais made their debuts for Smash, when the Triple Tails stable attacked Yusuke Kodama and Makoto after their matches, with the trio being both times chased out of the ring by Tajiri.

[52] In March, Triple Tails took part in Osaka Pro Wrestling's Spring Samba Series, going undefeated in six person tag team matches for the duration of the tour.

[51] On July 23, Triple Tails held a press conference to announce that, following the group's third self-produced event on September 18, Io was leaving the stable in order to pursue a singles career.

[17] On October 14, 2010, Shirai, working under the ring name Viva Kasai, made her debut for International Wrestling Revolution Group (IWRG) at an event in Naucalpan, Mexico, where she teamed with Mini Abismo Negro, Monster Clown and Yuriko to defeat El Hijo de Cien Caras, Mari Apache, Mascarita Divina and Pasión Cristal via disqualification in an eight-person tag team match.

[79][80] Later that same day, Shirai also took part in Lucha Fan Fest 8, where she, Dos Caras and Vanely defeated Atenea, Iwatani and Brazo de Plata in a six-person tag team match.

[84][85] On March 4, Shirai produced her own independent event named Carino!, which celebrated her fifth anniversary in professional wrestling and during which she officially aligned herself with Stardom, ending her freelancing days.

[86] Following her May 2012 drug arrest and eventual acquittal, Shirai made her in-ring return on July 22, taking part in a Stardom Rumble to determine the final four participants in the 2012 5Star Grand Prix.

[88] On October 27, Shirai and Mayu Iwatani entered the 2012 Goddesses of Stardom Tag League under the team name "Thunder Rock", defeating previous year's finalists, Kawasaki Katsushika Saikyou Densetsu (Natsuki☆Taiyo and Yoshiko) in their opening round-robin match.

[126][129] On May 17, Shirai made her record-setting eighth successful defense of the World of Stardom Championship by defeating Star Fire at Lucha Fan Fest 7 in Mexico City.

[140][141][142] On November 3, Shirai and Yoshiko, whose partnership was now officially known as "Heisei-gun" ("Heisei Army"), unsuccessfully challenged Shōwa-gun's Kairi Hojo and Nanae Takahashi for the Goddesses of Stardom Championship.

[145] On December 7, Shirai once again became a double champion, when she and Heisei-gun stablemates Mayu Iwatani and Takumi Iroha defeated Tomodachi Mania (Hatsuhinode Kamen, Kaori Yoneyama and Tsubasa Kuragaki) to win the Artist of Stardom Championship.

[154] On May 6, Shirai and Iwatani first defeated Oedo Tai (Kris Wolf and Star Fire) and then Candy Crush (Chelsea and Kairi Hojo) to win a tournament for the vacant Goddesses of Stardom Championship.

[163][164] During the second event in Baldwin Park, California two days later, Shirai and Iwatani made their fifth successful defense of the Goddesses of Stardom Championship against Hiroyo Matsumoto and Kellie Skater.

[171][172] Meanwhile, Thunder Rock also continued their reign as the Goddesses of Stardom Champions, defeating the rookie team of Jungle Kyona and Momo Watanabe on January 10, 2016, for their seventh successful title defense.

[176] In April, Shirai, along with Iwatani and Hojo, traveled to the United States to take part in events held by Lucha Underground and Vendetta Pro Wrestling.

After losing to Kairi Hojo and Yoko Bito, Shirai turned on Iwatani, declared that Thunder Rock and Threedom were history and formed a new partnership with an unidentified masked woman.

[190][191] On November 20, 2016, Shirai and her new partner, now revealed as the former Reo Hazuki and renamed "HZK", were joined by Momo Watanabe, who turned on Mayu Iwatani during a tag team match.

[203] Queen's Quest, now represented by Shirai, AZM and HZK, regained the title six days later by defeating Oedo Tai (Hana Kimura, Kagetsu and Rosa Negra) in the finals of a four-team tournament.

[236] In her first appearance for NXT, Shirai debuted on November 17, 2018, at TakeOver: WarGames where she and Dakota Kai saved her best friend Kairi Sane during her match with Shayna Baszler from an assault by her allies Jessamyn Duke and Marina Shafir.

[286] On February 14, 2021, at TakeOver: Vengeance Day, Shirai defeated Mercedes Martinez and Toni Storm in a triple threat match to retain the NXT Women's Championship.

They defeated the team of Amari Miller and Lash Legend in the first round,[301] Kacy Catanzaro and Kayden Carter in the semi-finals,[302] and Wendy Choo and Dakota Kai in the finals to win the tournament.

[312][313] On the September 12 episode of Raw, Sky and Kai defeated Women's Tag Team Champions Aliyah and Raquel Rodriguez in a rematch to win the championship.

[328] On August 5 at SummerSlam, Sky cashed-in her Money in the Bank contract on Bianca Belair following a triple threat match involving Asuka and Charlotte Flair to win her first WWE Women's Championship.

Sky would go on to turn face for the first time on the main roster with the rest of Damage CTRL on the July 29 episode of Raw when they began feuding with the newly-formed Pure Fusion Collective, consisting of Shayna Baszler, Zoey Stark and Sonya Deville, the latter of whom made her return from injury.

On the October 14 episode of Raw, Sky and Sane failed to win the WWE Women's Tag Team Championship from Bianca Belair and Jade Cargill after a distraction from NXT's The Meta-Four (Jakara Jackson and Lash Legend).