While the cast has rotated quite a bit over that time, Leroy Jethro Gibbs, played by Mark Harmon, has been a staple ... the murders of Gibbs's wife and child, right when he's beginning his career ...

Along with the late David McCallum, Mark Harmon is arguably the actor ... In short, though, Harmon is a poster child for this franchise, and that's why fans were shocked when he parted ways ...

Mark Harmon starred alongside Sean Connery in the 1988 flop that earned a 1.5-star rating from Roger Ebert and a 41% Rotten ...