Jumping forward several years into Season 12, we meet General Hospital actor Hudson West, who was lucky enough to play the teenage version of Callen. This is one of the few episodes where we see an emotional crack in the stoic Callen facade. After learning about the many foster homes Callen barely survived, we get to meet one of his foster brothers, who’s been framed for drug smuggling along with his wife. There are a lot of touching moments and insights into Callen’s personality here that Hudson West pulls off beautifully.
Since his appearance on NCIS: LA, Hudson has gone to guest star on 9-1-1 and is currently in pre-production on an anthology series called Like It Was Yesterday.
Source: https://www.distractify.com/p/who-plays-young-callen-ncis-la