lol Haven't seen the show, but I've always thought of Mark Harmon as a surfer due/laid back guy. Definitely not the kind of name that fits him. No offense to any Jethro's out there...
Well, I've never really thought of him as a surfer, but did you ever see him in The Deliberate Stranger as Ted Bundy. That character has always stayed in my head. He was so swave and smooth. Now as Jethro, he's just so tough and cool.
Out of his whole career, the role I remember him most for, was a teacher named Mr. Shoop in the movie "Summer School" back in the mid 1980's. I remember thinking back then how cool of a teacher he would have been if he were teaching at my school! LOL