Cusack began training for a professional wrestling career inBray in 2014, eventually travelling toEngland to attend more wrestling schools.[4] After training at theFight Factory Pro Wrestling (FFPW) gym, Cusack made her debut on 2 May 2015 in amixed tag team match withLJ Cleary for Celtic Cross Wrestling (CCW), defeating Katey Harvey and Michael Mayhem.[3][5] She adopted the ring nameValkyrie Cain, named after theprotagonist of theSkulduggery Pleasant book series byDerek Landy,[6] primarily wrestling Harvey acrossindependent promotions in her native Ireland.[5] By November 2016, Valkyrie began working with Harvey as atag team in Pro Wrestling Unlimited (PWU).[7]
Valkyrie in January 2018
Valkyrie challenged for several women's championships throughout 2017 and early 2018, but was unsuccessful.[8][9] However, in August 2018, she pinned male wrestlerJordan Devlin in asix-way match to capture FFPW's Irish Junior Heavyweight Championship, and Lauren La Roux the following month for the PWU Women's Championship.[9][10] In May 2019, Valkyrie made herWestside Xtreme Wrestling (wXw) debut during the Road to True Colors inBielefeld, defeating Amale Winchester andKiller Kelly in aThree-Way Dance.[11] She unsuccessfully challenged for the wXw Women's Championship at two events in June.[12][13]
In the same month, Valkyria debuted for thewomen's professional wrestlingpromotionPro-Wrestling: EVE, teaming with Debbie Keitel as the Woke Queens and winning thePro-Wrestling: EVE Tag Team Championship in October 2019.[14] They lost the titles toGisele Shaw and Sammii Jayne in December.[14] On 1 February 2020, Valkyrie competed in her final match in EVE, defeating Harvey.[15] She made her last independent circuit appearance on 8 March for wXw, teaming with Baby Allison in a loss to Kelly and Stephanie Maze.[16]
Prior to her signing with the company, Cusack participated in aWWE tryout inLondon in June 2019.[4]
Cusack was reported to have signed with WWE on 20 January 2020, and was assigned toNXT UK under the ring nameAoife Valkyrie.[1] She competed in her first match on 13 February episode ofNXT UK, defeatingAmale.[17] In February, Valkyrie toured withNXT for the first time, wrestling on twohouse shows inFlorida. Valkyrie defeatedAliyah on 14 February inTampa, followed by teaming withMia Yim and Rita Reis (later known as Valentina Feroz) to defeat Jessi Kamea,MJ Jenkins andTaynara in asix-woman tag team match on 15 February inFort Pierce.[15] She made her return to television on 17 September episode ofNXT UK in a winning effort againstIsla Dawn.[18] She remained undefeated until losing toMeiko Satomura on 29 April 2021 episode.[19] Later that year, Valkyrie suffered atorn ACL and did not wrestle for a year.[20]
After NXT UK closed in late 2022, she moved to NXT under the new ring nameLyra Valkyria,[21] defeating Amari Miller in her debut match on 13 December episode ofNXT.[22] At theNXT Stand & Deliverpay-per-view on 1 April 2023, Valkyria competed in aladder match for theNXT Women's Championship, but failed to win the title.[23] She took part in an eight-womansingle-elimination tournament for the vacated title, losing toTiffany Stratton in the finals on 28 May atNXT Battleground.[24] After defeatingIndi Hartwell andRoxanne Perez in a triple threat match proposed by championBecky Lynch,[25] Valkyria bested Lynch at Night 1 ofNXT: Halloween Havoc on 24 October to win the NXT Women's Championship.[26] She made her first successful title defense againstXia Li on 21 November episode.[27] AtNXT: New Year's Evil on 2 January 2024, she retained the title againstBlair Davenport. After the match,Tatum Paxley, who had been obsessed with Valkyria since December,[28] stoppedLola Vice from cashing in herBreakout Tournament contract.[29] AtNXT Vengeance Day on 4 February, Valkyria retained the title against Perez and Vice, who cashed in while the match was in progress to make it a triple threat.[30] On 5 March atNXT: Roadblock, Valkyria and Paxley failed to win theWWE Women's Tag Team Championship fromThe Kabuki Warriors (Asuka andKairi Sane) after Valkyria inadvertently kicked Paxley. After the match, Perez attacked Valkyria and injured her arm.[31] AtNXT Stand & Deliver on 6 April, Valkyria lost the NXT Women's Championship to Perez by submission, ending her reign at 165 days.[32] Paxley turned on Valkyria the following week and eventually revealed that her obsession with Valkyria was only because she had the NXT Women's Championship.[33][34] Valkyria wrestled her final NXT match at Week 1 ofSpring Breakin' on 23 April, where she failed to regain the title from Perez in a triple threat match also involving Paxley.[35]
On 11 April episode ofSmackDown, Valkyria and Bayley won agauntlet match to faceLiv Morganand Rodriguez for the WWE Women's Tag Team Championship at Night 2 ofWrestleMania 41 on 20 April.[47] Prior to Night 1 of WrestleMania 41, Bayley was taken out backstage and was unable to compete.[48] The following day, Lynch, who had been on hiatus for nearly a year, returned as Valkyria's new tag team partner, defeating Morgan and Rodriguez to win the titles, making Valkyria a double champion.[49] However, the duo lost the titles back to Morgan and Rodriguez the next night onRaw, ending their reign at only one day, marking the shortest reign in the title's history. Immediately after, Lynch turned on Valkyria.[50] On 10 May atBacklash, Valkyria defeated Lynch to retain the title, but was subjected to a post-match assault by Lynch.[51] She lost the Women's Intercontinental Championship to Lynch in aLast Chance match on 7 June atMoney in the Bank, ending her reign at 145 days. After the match, per stipulation, Valkyria acknowledged Lynch as the better woman and raised her hand, but attacked Lynch afterwards.[52] AtEvolution on 13 July, she failed to regain the title from Lynch in a triple threat match also involving Bayley.[53] The next night onRaw, Valkyria defeated Bayley in atwo-out-of-three falls match to earn a rematch against Lynch for the title atSummerSlam.[54] At Night 2 of the event on 3 August, Valkyria failed to win the title in a no disqualification Last Chance match, therefore being unable to challenge for the title as long as Lynch is champion, ending their feud.[55]
Cusack attendedDublin City University, where she studiedjournalism.[3][20] She is in a relationship with fellow professional wrestlerLJ Cleary; they announced their engagement on 14 September 2024 after ten years of dating.[58]