Mackenzie Christine Foy was born 10 November 2000. She began her career as a child model in 2004, working for Garnet Hill, Polo Ralph Lauren, and Guess Kids. She has also modelled in print ads for companies such as Rubbermaid, Jones Apparel Group, The Walt Disney Company, Mattel, Target Corporation, Talbots, Guess, and Gap.
Foy got her start appearing in commercials. Her first acting role came in 2009 in the TV series 'Til Death (2006). She has guest starred on Hawaii Five-0 (2010) and R.L. Stine's The Haunting Hour (2010). At age 11, she landed her breakthrough role as Renesmee, the daughter of Bella and Edward in The Twilight Saga: Breaking Dawn - Part 1 (2011) and The Twilight Saga: Breaking Dawn - Part 2 (2012). She filmed The Conjuring (2013) and lent her voice to The Boxcar Children (2014), along with her Conjuring co-star Joey King.
She had a starring role alongside Ellen Burstyn as Lou Cardinal in Wish You Well (2013). She also lent her voice to the English versions of the French films Ernest & Celestine (2012) and The Little Prince (2015). Her next starring role of Murph came opposite Matthew McConaughey as the young version of his daughter in Interstellar (2014). The all-star cast included Anne Hathaway, Michael Caine, and John Lithgow.Jessica Chastain played the adult version of Foy's character and Ellen Burstyn, her Wish You Well (2013) co-star, played the oldest version.
Foy was able to add more impressive A-list co-stars in her last film before she turned 18. She can be seen as the lead role of Clara in The Nutcracker and the Four Realms (2018), along side Morgan Freeman, Helen Mirren, Eugenio Derbez and Keira Knightley.
In addition to focusing on her studies to graduate high school in the spring, Foy spends her time painting, playing with her dog, and doing Tae Kwon Do, a martial art she holds a third-degree black belt in.