Alexa debuted on NXT in 2014, and after a year as a babyface, Alexa began turning into a villainess on the April 30, 2015 episode of NXT, doing so in a backstage segment with Carmella. After confronting Carmella, Alexa was seen with reigning NXT Tag Team Champions Blake and Murphy, who were feuding with Carmella's associates, Enzo Amore and Big Cass. Two weeks later on the May 13 episode of NXT, Alexa defeated Carmella in a grudge match, with the win coming after Blake and Murphy distracted Carmella.
At NXT Takeover: Unstoppable on May 20, Alexa turned villainous during Blake and Murphy's NXT Tag Team Championship defense against Enzo and Big Cass. During the match, the evil Alexa attacked Carmella at ringside and did the same to Enzo to allow the tag champs to retain, cementing her alliance with Blake and Murphy. In later weeks, Alexa would constantly get involved in Blake and Murphy's matches, and would attack their opponents after they were defeated. She later engaged in a feud with Blue Pants, after she prevented Alexa's interference at NXT Takeover: Brooklyn, leading to the Vaudevillains capturing the tag titles. Alexa defeated Blue Pants in a grudge match on NXT two weeks later. Alexa later chased the NXT Women's Championship, which was held by Bayley at the time. After weeks of antagonizing Bayley, Alexa received her title opportunity on the November 18, 2015 edition of NXT, but she was defeated by Bayley.
After months of competing on NXT, Alexa was drafted to the SmackDown brand on July 19, as part of the returning brand split. In her first main roster match on the program, Alexa defeated Becky Lynch in singles action. Her main roster PPV debut came at SummerSlam, as she, Natalya, and the returning Nikki Bella defeated Carmella, Becky Lynch, and Naomi. Alexa competed in a six-pack challenge match at Backlash to crown the first ever SmackDown Women's Champion; the match was won by Lynch. In the months that followed, Alexa continued feuding with Lynch over the title, which Alexa finally won at TLC in a Tables Match.
Alexa's feud with Becky continued in December, when a week after intentionally getting counted out in a title rematch, she was defeated by a woman known as La Luchadora, who was revealed as Becky Lynch. On December 27, Alexa successfully defended the title against Lynch in another rematch, with the win coming after Lynch was attacked by a villainess dressed as La Luchadora. On the following week, after Lynch defeated the villainous La Luchadora, Alexa and the masked villainess attacked Lynch. On January 17, Alexa defeated Becky in a Steel Cage match for the title after La Luchadora again interfered. La Luchadora was unmasked by Becky and revealed as the evil Mickie James, who aligned with Alexa in attacking Lynch.
After suffering back to back losses to Naomi, Alexa ended up defending the title against Naomi at the Elimination Chamber, and lost the title to Naomi. Once Naomi had to surrender the title due to injury, Alexa competed for the vacant title against Lynch, defeating Lynch to become a two-time champion. Alexa lost the title to Naomi in a six-pack challenge at WrestleMania 33, and lost a title rematch to Naomi on SmackDown two nights later.
Alexa was moved to RAW during the Superstar Shake-Up, along with former ally Mickie James. A week later, Alexa defeated Mickie James, Sasha Banks, and Nia Jax to become the #1 Contender for Bayley's RAW Women's Championship. Alexa's title shot came at Payback on April 30; defeating Bayley to capture the title. In May she found she had to defend her title against the former champion Bayley yet again, and during this time she discovered a fondness for kendo sticks. More specifically she discovered how much she enjoyed hitting other women with them, and admitted in an interview that "the sound of the stick striking her flesh makes me salivate". At Extreme Rules 2017 Alexa made quick work of Bayley, dominating her with a kendo stick to retain the RAW Women's Championship