Braddy was born Johanna Elizabeth Braddy in Atlanta, Georgia to Jo Beth, a preschool music teacher and a vocalist, and Steve Braddy, an engineer. She has one brother, Cole Braddy, who is eight years her junior. Braddy attended the McIntosh High School in Peachtree City, Georgia and graduated in 2005 where she was the captain of her high school dance team and an active member of McIntosh's drama program under director Stephen Buckner.
Braddy's film debut was in the film Pop Rocks in which she portrayed Olivia Harden, with her role as Yue in Avatar: The Last Airbender marking her television debut. Braddy has landed many other roles including those in films such as Surf's Up, Broken Bridges, Home Of The Giants, and The Oaks, among others.