Several years before making his debut on Ozzie's Girl, Mark, then barely a high school student, made his commercial debut for a Kellogg's ad, alongside his dad Tom Harmon. Tom, who passed away ...

NCIS' Mark Harmon reportedly shares many similarities with his character in the series Leroy Jethro Gibbs, including his biggest hobby.

Mark Harmon expected NCIS to be dark and gritty — then it became a quippy crime procedural. Not what he signed up for, but it ...