There may be three shows currently airing in the NCIS franchise, and CBS may host the occasional crossover (including the upcoming event with the longest and latest shows), but that doesn’t mean that they necessarily share the same characters.
Over the years, many of the same actors have appeared across the franchise, sometimes in different roles — especially when the guest star’s original character died. Sometimes they’ve played a very different role, and at other times they’ve still been the good or bad guy.
NCIS: Los Angeles, Sundays, 9/8c, CBS
NCIS, Mondays, 9/8c, CBS
NCIS: Hawai’i, Mondays, 10/9c, CBS