Deadline confirmed that Mark Harmon will be narrating each episode of NCIS: Origins, which means he will technically be playing Gibbs in new stories, even if we only hear his voice. It’s a structure that is somewhat similar to The Adventures of Young Indiana Jones (1992-96), in which actor George Hall narrated as the older version of the character.
Considering that the odds were slim that Harmon would return to NCIS in a full-time capacity, getting him to narrate prequel stories as a wet-behind-the-ears Gibbs is the next best thing! We can’t wait for the show to premiere in 2025.