Gardner was born in Los Angeles, California. She began acting on television at an early age. Appearing in a recurring role on Viper and guest-starred on ER. She later moved to New York City and graduated form the Juilliard School. Same time Gardner acted on stage appearing in such productions like For Colored Girls, The School of Night and The Seagull. She has appeared in a number of regional productions. Also, Gardner had a number of guest-starring roles on television shows such as Crossing Jordan, Bones, Heroes and Castle. Gardner worked as a voice actress playing Steela Gerrera in the Star Wars: The Clone Wars. In 2016, Gardner was cast as a lead in the Oprah Winfrey Network drama series, Queen Sugar.
