Jamia Simone Nash appeared on the CBS soap opera The Young and the Restless as Ana Hamilton. She began singing at the age of two; her first national appearance was on Showtime at the Apollo in 2002, where she sang the Alicia Keys song Fallin'. Nash performed at the 2003 Essence Awards, singing Michael Jackson's song "Who's Lovin' You" in honor of Mary J. Blige. She and her younger sister Olivia sing the hook of the song "Black Girl Pain" on Talib Kweli's 2004 album The Beautiful Struggle.
Nash played a ten-year-old Fantasia Barrino in the 2006 made-for-television film Life Is Not a Fairytale: The Fantasia Barrino Story, a biopic about the 2004 American Idol winner. In the 2007 movie August Rush, Jamia's character Hope is the lead vocalist on the song "Raise It Up". Jamia performed "Raise It Up" from the film August Rush at the 2008 Academy Awards, making her the youngest person ever to perform on an Academy Awards telecast. Also at the Academy Awards, she was shown on stage playing tennis via Wii Sports with the host Jon Stewart. Jamia's song "Bongo Bird" was featured as a video on the Noggin series Jack's Big Music Show.