Sean Murray has officially surpassed Mark Harmon as the top-billed star on NCIS. Despite Harmon leaving the show in 2021, he was still credited throughout the entire Season 19, which skews his episode count. Murray now has 438 credited episodes, second only to David McCallum. The news has surprised many, as Harmon led the series. However, Murray's performance and growth in the role have been praised by fans. He is seen as the backbone of the show and is appreciated for his humility and dedication to the role.