[6] Foy began modeling in print ads in 2004, working for Garnet Hill, Polo Ralph Lauren and Guess.

[9] Foy's acting career began when she was nine years old, when she guest-starred in television shows such as 'Til Death, FlashForward and Hawaii Five-0.

In 2010, she was cast as Renesmee Cullen in the film adaptation of Stephenie Meyer's book Breaking Dawn, the fourth and final novel in the Twilight saga series.

In February, she was also in the last episode of the second season of the horror TV series R. L. Stine's The Haunting Hour, in which she played Natalie, a girl who goes to live with her grandfather and discovers that one of the dolls is alive and has bad intentions.

[15][16] In May 2019 it was announced that Foy would co-star with Kate Winslet in a new adaptation of Black Beauty, which was filmed in the fall of 2019 and was released in 2020.