Gabriel was born in Burbank, California, and is of Italian, Mexican and French descent. She graduated from Burbank High School. Gabriel appeared as Princess Yue in the movie The Last Airbender (2010), directed by M. Night Shyamalan. The film was based on Avatar: The Last Airbender, an animated children's television series. Gabriel appeared in Honey 2 (2011), directed by Bille Woodruff, produced by Universal Studios Home Entertainment.
Gabriel also appeared in the films The Spirit (2008), as Young Sand Saref. She has performed on The Tonight Show, a late-night talk show, and had a recurring role on the comedy-drama television series Weeds. She has also appeared in one episode of Zoey 101, a situation comedy. She provides the voice for Asami Sato in The Legend of Korra. Gabriel currently appears as a series regular on the original TNT sci-fi action/drama series Falling Skies produced by Steven Spielberg which began airing in June, 2011.