[2] According to an article published by the Smithsonian Asian Pacific American Center, she was "born at home in a commune to non-hippy parents.
After graduating, she moved to Los Angeles and eventually landed a job as a character designer on the Adult Swim series Metalocalypse after she drew a card for the series' lead character designer, Songgu Kwon.
After an indie comic of hers was well received by Pendleton Ward, she was hired as a storyboard revisionist on the Cartoon Network series Adventure Time.
[4] She was eventually promoted to storyboard artist, and served in that position until she left in 2013 to focus fully on her art career.
At the inaugural Children's and Family Emmy Awards ceremony held in 2022, Castuera received an Emmy for "Outstanding Directing for an Animated Program" (alongside Luis Grane, Elizabeth Ito, Bob Logan, and Pendleton Ward).