A native of Gardena, California, Castillo began playing drums at age 15, when his grandmother loaned him the money to buy a drum kit.
His playing is influenced by War, Al Green, Led Zeppelin, the Rolling Stones, and Black Flag.
He started off his drumming career by joining the Los Angeles punk band Wasted Youth in 1984.
After recording two albums and several tours, he left Wasted Youth and joined Sugartooth. During the summer of 1994, he formed a short-lived punk rock band called Chronic Halitosis. They played punk covers of bands like Misfits and Black Flag.
In 1994, Castillo left Sugartooth and joined Danzig, having turned down previous offers from Slayer and Suicidal Tendencies.
In 1996, he was featured on Robert Trujillo's solo album, and in 1998 he joined Zilch.
He replaced Goatsnake's original drummer after his departure in 2001, but that was short lived when they split up shortly after. In 2001 he did backing vocals and drums for some tracks on Son of Sam's album Songs From The Earth.
Castillo joined Queens of the Stone Age without an audition, playing through half a song (Avon) at an informal rehearsal before frontman Josh Homme walked out of the room, returned saying "I just fired the drummer. The tour starts tomorrow," and offered Castillo the gig. Castillo also played on Mark Lanegan's solo album Bubblegum and Eagles of Death Metal's second album Death by Sexy.
On June 25th, 2017, Castillo, along with Trent Reznor, Mariqueen Maandig Reznor, Robin Finck, Atticus Ross, and Alessandro Cortini appeared as "The Nine Inch Nails" in Episode 8 of Twin Peaks: The Return on Showtime, performing an alternate live rendition of the song "She's Gone Away" which previously appeared on Nine Inch Nails' 2016 album "Not the Actual Events".
In 2015, he was a touring replacement for Jason Bonham in the Glenn Hughes project, California Breed. Bonham quit before the tour to join Sammy Hagar and Hughes wanted the tour that supported Alter Bridge to continue as planned.
Castillo resides in Joshua Tree National Park, California.