Shortly after, Castile appeared in the Miller-Boyett sitcom Going Places in early 1991, playing the recurring role of Sam Roberts, the son of talk show host Dick Roberts (Steve Vinovich) with co-stars Alan Ruck and Heather Locklear. Castile and his fellow Going Places cast member Staci Keanan were soon moved by Miller-Boyett into their forthcoming sitcom Step By Step, that premiered on ABC in the fall of 1991. He and Keanan played brother and sister Mark and Dana, on the Foster family side, for the entire run of Step by Step, which moved to CBS in 1997 and then ended in 1998.