In honor of NCIS' 20th anniversary, the show's creators discussed the early days of the series and revealed why Mark Harmon was chosen for the role of Gibbs. The casting process was challenging, and Harmon had been on their radar since the beginning. Other actors considered for the role included Harrison Ford, Alec Baldwin, Chris Cooper, and more. Ultimately, Harmon's meeting with show creator Don Bellisario sealed the deal.

While Harmon recently left the show in its 19th season, his portrayal of Gibbs made a lasting impact on fans. NCIS is available for streaming on CBS in the US and Disney+ in the UK.