A California native, Costello began writing songs as early as thirteen years old. Eventually she began performing her songs around Los Angeles, and when she turned seventeen, released her debut full-length album, Kaleidoscope Machine. A year later, Katie would leave the insular nature of Los Angeles to find new inspiration and cultural diversity in New York City’s Lower East Side. Upon moving to New York, Katie’s creativity blossomed into something tangibly beautiful, resulting in her second full-length album Lamplight, produced by Tony Berg, along with the release of various EP's and singles.
Katie Costello’s infectious brand of “Rebel Pop” has also made appearances on Private Practice, Pretty Little Liars, Switched at Birth, Vampire Diaries, One Tree Hill, 90210, Home and Away, and Rookie Blue, along with appearances in films: Brooklyn Brothers Beat the Best, Craigslist Joe, As Cool As I Am, Never and others.