[1] His family settled in Yuba City, California, where his mother worked at a prune factory off Highway 113.
[5] He has taught as a resident artist at the Atlantic Center for the Arts in Florida,[6] and for low-income high school students in the Upward Bound program at UC Davis.
[6] Castillo's manuscript, Cenzóntle, was selected by Brenda Shaughnessy as the 2017 winner of the A. Poulin, Jr. Poetry Prize, from BOA Editions.
[9] A Pushcart nominee, Castillo has received fellowships from CantoMundo, the Squaw Valley Writer's Workshop, and the Vermont Studio Center.
Castillo was a founder, with poets Javier Zamora and Christopher Soto (AKA Loma), of the Undocupoets campaign which eliminated citizenship requirements from major first poetry book prizes in the United States.