The executive producer of NCIS, Charles Floyd Johnson, has revealed that Harrison Ford was considered for the role of Leroy Gibbs before Mark Harmon was cast. Johnson explains that Ford's name was thrown around, but Harmon was ultimately chosen instead. While it's unclear how Ford's portrayal of the character would have differed, Harmon's performance has become a staple of the franchise. Harmon recently exited NCIS, but there is potential for him to return in the future. Ultimately, Harmon was the right choice for the role of Gibbs.