In 2012, Carson was signed with BMI as a "singer-songwriter". Her acting career was launched in 2014 when she was cast as guest star, playing Chelsea, on the Disney Channel series Austin & Ally. A few months later, Carson was cast as recurring guest star, playing Soleil, on MTV's series Faking It. In 2014, she was cast in a starring role in the Disney Channel Original Movie Descendants, in which she plays Evie, the daughter of the Evil Queen from Snow White.
Carson has performed in NBC's 2015 Thanksgiving Parade, ABC's Disney Parks Christmas Celebration, Univision's Feliz 2016 (New Year's Eve Special) and the 2016 Radio Disney Music Awards, and was a presenter on ABC's Disneyland 60th Anniversary Special. She performed "The Star-Spangled Banner" at the 2017 A Capitol Fourth, an annual concert at the United States Capitol in celebration of Independence Day.
Carson reprised her role as Evie in the 2017 sequel Descendants 2. On August 25, 2017, her record label released her single "Ins and Outs". In January 2018, it was announced that Carson would be starring in the upcoming Freeform television series Pretty Little Liars: The Perfectionists.