

McNamara began her acting career on stage in Kansas City. In July 2017, she said that she was enrolled in an online master's degree literature program at Johns Hopkins University. At age 17, McNamara graduated summa cum laude with a Bachelor of Science degree in Business Administration from Drexel University, completing much of her course work online.

While growing up, McNamara was an advanced student in certain subjects, resulting in her being partly homeschooled she received her high school diploma at age 14. She was raised in Lee's Summit, Missouri, and moved to Los Angeles, California in 2011. McNamara was born in Kansas City, Missouri, the only child of Ursula and Evan McNamara, who served in the U.S. Her film roles include Lily Bowman in the 2011 romantic comedy New Year's Eve, Rosa in the 2015 drama A Sort of Homecoming, Sonya in the dystopian science fiction film series Maze Runner, and Amy in the 2021 thriller Trust.

She also portrayed Mia Smoak in the superhero series Arrow and starred as Julie Lawry in the post-apocalyptic miniseries The Stand. Since 2022, she has starred in the western action series Walker: Independence as Abby Walker, which earned her a Critics Choice Super Award for Best Actress in an Action Series nomination. She portrayed Clary Fray on the 2016–2019 supernatural drama television series Shadowhunters, receiving a Teen Choice Award and a People's Choice Award for her work. Katherine McNamara (born Novem ) is an American actress.
