Mackenzie Foy was born on November 10, 2000. She was born and raised in Los Angeles. Foy began modeling at age 3, and started acting at age 9.

Foy began modeling in print ads in 2004, working for Garnet Hill, Polo Ralph Lauren and Guess. From there, she modeled for companies such as The Walt Disney Company, Mattel and Gap.

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. The first movie, The Twilight Saga: Breaking Dawn – Part 1, in which Renesmee is shown only in a flash forward, was released on November 18, 2011, while the second, The Twilight Saga: Breaking Dawn – Part 2, on November 16, 2012.

Foy co-starred in Christopher Nolan's Interstellar, about a team of explorers who travel through a wormhole in an attempt to ensure humanity's survival. Her character as an adult woman was portrayed by Oscar nominee Jessica Chastain. Her character as an elderly woman was portrayed by Ellen Burstyn, who had played her grandmother the previous year in Wish You Well. She provided the voice of Celestine in the English dub of Ernest & Celestine (2012), Violet in The Boxcar Children (2014) and The Little Girl in The Little Prince (2015). In July, it was announced that Foy would play Clara in the 2018 film The Nutcracker and the Four Realms with Morgan Freeman and Misty Copeland.