Notable for his portrayal of Richie Donado Ventura in the HBO series Looking, he is also known for his work in the films Cold Weather and Amexicano, as well as for his performances with New York's Ensemble Studio Theatre and Public Theater.
He began acting during his early teen years and was involved in numerous theatrical productions at his Texas high school. After graduating from Boston University, he made his professional theatrical debut in an Austin, Texas staging of Santos & Santos.
A Playwright as well as an actor, he developed his work Knives and Other Sharp Objects at the LAByrinth Theater Company.
Born in McAllen, Texas, he and his brother and sister are the children of Mexican immigrants Raul and Adela Castillo.
He co-starred with Sandra Oh in a 2014 Chicago stage production of Death and the Maiden.
