Because of this, Mark Harmon was permanently removed from NCIS !

​Mark Harmon, who portrayed Special Agent Leroy Jethro Gibbs on NCIS for nearly two decades, departed the series during its 19th season in 2021. His exit was a personal decision, not a forced removal. Harmon expressed a desire to reduce his workload and spend more time with his family, citing the demanding nature of the show’s production schedule as a factor in his decision. ​
Entertainment Tonight
In his final episode, titled “Great Wide Open,” Gibbs chooses to remain in Alaska after completing a case, telling his colleague McGee that he has found a sense of peace he hadn’t experienced since the loss of his wife and daughter. This narrative provided a fitting and heartfelt conclusion to his character’s journey. ​
People.com
Although Harmon stepped away from his on-screen role, he continues to be involved with the NCIS franchise as an executive producer. He is also set to narrate and produce the upcoming prequel series, NCIS: Origins, which explores the early career of Gibbs in the 1990s. ​
Entertainment Tonight
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In summary, Mark Harmon’s departure from NCIS was a voluntary decision driven by personal considerations and a desire to pursue other projects, rather than a forced removal from the series.​