It was this raw premise, based on "NCIS" lore, that made Harmon's son Sean, who had played the young Gibbs in "NCIS" flashbacks, pitch "Origins." (He's now an executive producer.) Young Gibbs ...
Mark Harmon played Gibbs on NCIS; Austin Stowell now plays the younger Gibbs on NCIS: Origins. SeanHarmon (Mark’s son) used to play Gibbs in NCIS flashbacks, but he now serves as an ...