Castillo is 25-years-old and hails from Buffalo, New York. He was a standout athlete at Lancaster Central High School both on the diamond and the gridiron, even receiving an offer to play College Football at the University of Oklahoma with Lincoln Riley. Castillo elected to sign with the Milwaukee Brewers after they had selected him in the 2017 MLB Draft. 

The speedster was in the Brewers system for a few years and in 2021 with the Wisconsin Timber Rattlers, he had a .280 batting average, nine home runs, and 13 doubles. Castillo would move to the Frontier League and play in 20 games with the Washington Wild Things before he found a longtime home with the RailCats.  

The slugger was named to the 2023 All-Star game as the last man in, and last year he had a .249 average, with three triples, and drive in 40 runners. Since the RailCats became a member of the American Association in 2013, Castillo ranks 7th in hits(254), 8th in games(240), and 8th in RBIs(126).