Stephanie Bell trained for eighteen months before making her debut on August 22, 2009, adopting the ring name Mia Yim, wrestling mainly in local federations that are part of the independent circuit in Virginia. She later wrestled for Jersey All Pro Wrestling, facing wrestlers such as Annie Social, Angeldust and Brittany Force. During this time, she meets Daizee Haze, through whom she begins working in Ring of Honor.

Yim made her Shimmer Women Athletes debut on April 6, 2013 at Volume 53 in a losing effort to Amazing Kong. As of April 2015, she joined the Total Nonstop Action Wrestling roster. In the episode of IMPACT! on April 10, she appears in a promo with Marti Bell, under the ring name Jade, calling herself The Dollhouse, thus establishing herself as a heel tag team.

On November 5, 2021, she was fired along with numerous other colleagues.

She returned to WWE on the November 7 episode of Raw helping The OC fight Judgment Day. She wrestled her first match since her return the following week on Raw, defeating Tamina and later teamed with Bianca Belair, Alexa Bliss and Asuka in preparation for the fight against the Damage CTRL (Bayley, Dakota Kai and Iyo Sky) and Rhea Ripley of Survivor Series WarGames.

On April 28, 2023, as a result of the Draft, Michin moved to the SmackDown roster.

Stephanie is half Korean and half African American. She has Korean ancestry due to her mother, and she speaks her language fluently. Bell is romantically linked to colleague Keith Lee, with whom she has been married since February 5, 2022.