[12] She started appearing in television commercials at the age of 10, for products including Hasbro, Kidz Bop 14, Mattel, Bratz dolls, Littlest Pet Shop, and Girl Gourmet.

[13][14] Possessing skills in gymnastics, Holt was cast in Disney XD's martial arts comedy Kickin' It, which premiered on June 13, 2011.

[17] She left Kickin' It as a regular after season 3 to star in the Disney Channel half-hour comedy series I Didn't Do It, which premiered on January 17, 2014.

[23] Holt and co-star Aubrey Joseph reprised their roles in the animated series Spider-Man and a crossover episode in Runaways.

Holt plays Kate Wallis on the series Cruel Summer, a psychological thriller set between 1993 and 1995 that premiered on Freeform on April 20, 2021.

[24] In November 2014, Holt joined the cast of the drama Same Kind of Different as Me, directed by Michael Carney and also starring Greg Kinnear and Renée Zellweger,[25] who play her character's parents in the film.

[27] In November 2015, it was announced that Holt had been cast in a lead role in the indie comedy Class Rank, directed by Eric Stoltz.

[28] In May 2016, it was announced that she would star alongside Ross Lynch in Status Update, directed by Scott Speer, with filming to commence the following month in Vancouver, Canada.

[29][30] From 10 December 2014 to 4 January 2015, Holt played Aurora in Sleeping Beauty and Her Winter Knight at Pasadena Playhouse.

[37] She and Forever in Your Mind also performed at the 2016 TJ Martell Family Foundation Day in Los Angeles on October 9, 2016.

[38] In April 2017, she was picked as Elvis Duran's Artist of the Month appearing on NBC's Today show with Hoda Kotb and Kathie Lee Gifford performing her hit "History".