Thomas Mark Harmon is an American actor, producer, director and former football quarterback. He is best known for playing the lead role of Leroy Jethro Gibbs in NCIS. He also has appeared in a wide variety of roles since the early 1970s.

Is Mark Harmon a real Marine?

Though Mark Harmon never served in the military, his father, Tom Harmon, was a pilot in World War II. Prior to his service, Tom Harmon was an incredible football player and played for the University of Michigan from 1938 to 1940.

Are Mark and Angie Harmon related?

Many fans have wondered whether Harmon is related to another actor from the crime genre, NCIS's Mark Harmon. ... Despite their shared last name, Angie and Mark are not related.