Castle was born in the Beverly neighborhood on Chicago's south side. He attended Brother Rice High School graduating in 2007. Castle began his career in 2011, playing Randy in the short called The Ghosts. The following year, Castle was in the 2012 television movie Family Trap. He also was in an episode of the television show Harder Than It Looks, playing the delivery guy. In 2014, Castle was in an episode of the television series Sirens. Castle also portrayed Randy in the television mini-series Hope & Randy in 2014. Castle starred as A.J. Salerno in the TBS television series Clipped, alongside Ashley Tisdale and fellow Beverly native George Wendt, in 2015.