Mark Harmon, best known as Leroy Jethro Gibbs on NCIS, is deepening his connection with the franchise. While his on-screen role has ended, he will return as the narrator for NCIS: Origins, a prequel series exploring the early adventures of Gibbs and Mike Franks. This new endeavor allows Harmon to stay connected to the show’s legacy in a fresh way.

Harmon has also ventured into writing, collaborating with longtime NCIS technical advisor Leon Carroll Jr. Their first book, Ghosts of Honolulu: A Japanese Spy, a Japanese Spy Hunter, and the Untold Story of Pearl Harbor, highlights Douglas Wada, the first Japanese American NIS agent. Released in late 2023, the book reflects Harmon’s commitment to showcasing authentic NCIS stories inspired by real-life cases.

The duo’s second book, Ghosts of Panama: A Strongman Out of Control, A Murd3red Marine, and the Special Agents Caught in the Middle of an Invasion, continues this mission. Harmon, once reluctant to write, embraced the opportunity to celebrate NCIS’s true history, evolving the project into a tribute to the agency’s enduring legacy.