Daddio was born in Paramus, New Jersey. She grew up in Elmwood Park, New Jersey. She has four older brothers and a younger sister, and following the death of her father, Daddio's mother was a single parent raising six children. Daddio is a longtime fan of professional wrestling, and would participate in backyard wrestling with her siblings. Daddio described the matches as core to start her foray into wrestling, saying:
"I would literally take pedigrees and powerbombs like it was my job. I always pretended to be Lita. All the Divas were so glamorous and girly, and I was such a tomboy and didn't have nice clothes. When I saw Lita come out in baggy pants and sneakers, wrestling the boys, I thought she was the coolest thing ever. I related to her."
Daddio is a former competitive cheerleader, and she previously worked and modeled for the restaurant chain Hooters.
Professional wrestling career
After being discovered at Joe DeFranco's gym in Wyckoff, New Jersey, Daddio signed a contract with WWE in 2014, and was assigned to their developmental territory, WWE NXT, in October. She made her first televised appearance at the NXT TakeOver: Rival event on February 11, 2015, as a planted fan who jumped on Tyler Breeze during his ring entrance. She later appeared at NXT TakeOver: Unstoppable on May 20, again as part of Breeze's entrance. In October, she briefly worked under the ring name Marley, debuting on the November 4 episode of NXT, where she worked as a jobber losing to Eva Marie.
Daddio would return a month later as Liv Morgan, on the December 2 episode of NXT, losing to Emma. On the January 13, 2016 episode of NXT, Morgan competed in a battle royal to determine the number one contender to Bayley's NXT Women's Championship, which was won by Carmella. On the August 17 episode of NXT, she competed in a six-woman tag team match along with Carmella, and Nikki Glencross, in which they defeated Daria Berenato, Mandy Rose, and Alexa Bliss. On the August 31 episode of NXT, Morgan picked up her first televised singles win, defeating Aliyah. On the September 14 episode of NXT, Morgan defeated Rachel Fazio in singles competition via submission, and would issue a challenge to the NXT Women's Champion Asuka. The following week, however, Morgan was submitted by Asuka in under a minute. Afterwards, she began a rivalry with Billie Kay and Peyton Royce, with both women confronting her following her match, and two weeks later, Kay defeated her after interference by Royce. She confronted the two on the October 26, 2016 episode, where she allowed Aliyah to beat Kay after a distraction, afterwards aligning with her.
- Finishing moves
- Guillotine choke proceeded by a jumping DDT
- Reverse roundhouse kick
- Signature moves
- Back handspring tilt-a-whirl headscissors takedown, sometimes as a counter out of the corner
- Belly-to-back suplex
- Drop toe-hold to an oncoming opponent
- Handspring back tilt-a-whirl headscissors takedown
- Jackknife hold
- Leg-feed enzuigiri
- Matrix evasion
- Monkey flip
- Running one-handed bulldog, sometimes followed by a kip-up
- Running two-handed bulldog to a kneeling opponent
- Single leg dropkick, sometimes done repeatedly in succession
- Sitout hip toss