It was announced that McNamara would playing the recurring role of Kat on the third season of The Fosters in 2015. McNamara was cast in the MTV series Happyland as Harper Munroe, a theme park photographer. She also appeared in an episode of the Nickelodeon series The Thundermans. She appeared on three episodes of the Disney XD series Kickin' It, in which she had a recurring role as Claire, Kim's rival, and in two episodes of the Disney Channel series Jessie, playing Bryn Brietbart, a rival to Emma Ross.

McNamara in an interview with Mingle Media in 2014 McNamara also appeared in the independent films Contest and A Sort of Homecoming. She co-starred in the film Tom Sawyer & Huckleberry Finn, playing the role of Tom's girlfriend Becky Thatcher. Monster, playing the role of Myra Santelli. McNamara appeared in theatrical movies such as New Year's Eve and in the Disney Channel original movie Girl vs.

She began making guest appearances in television series, including Law & Order: SVU, 30 Rock, and Drop Dead Diva. In 2010, she appeared in the 2009 Broadway revival of A Little Night Music with Catherine Zeta-Jones and Angela Lansbury. She then participated in motion picture productions filmed in the Kansas City area, such as Matchmaker Mary in 2008 and the short film 'Get Off My Porch'. 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. McNamara accolades includes, a Teen Choice Award and a People's Choice Award for her work on Shadowhunters. Since 2022, she stars 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. 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 has also starred as Julie Lawry in the post-apocalyptic miniseries The Stand. Katherine Grace McNamara (born Novem ) is an American actress, known for playing Clary Fray on the 2016–2019 supernatural drama television series Shadowhunters, and Mia Smoak in the superhero series Arrow.

Lollipop by Amy Lane