NCIS premiered in 2003 and Mark Harmon immediately became one of the show's fan-favorite characters! We might have been used to see him on screen, but at some point of his life he was actually not exactly sure about what to do professionally, and it seems he found his way to acting by a twist of fate!

The 68-year-old actor first followed in his father's footsteps and dedicated to football when he was in high school; he actually played quarterback for the Bruins at UCLA. Later on he considered entering the advertising world or even working as a lawyer, however, a series of circumstances led him to acting when one of his sisters married music star Ricky Nelson, and somehow started to be involved in the show business.

Mark Harmon has an impressive acting career

As Harmon once revealed, he would spend a lot of time with Nelson, who at that time was filming a television show called Ozzie's Girland when he needed a stand-in for one of the young actors on the series, he asked Harmon if he would be up for the role and the NCIS star agreed. That's how he discovered his passion for acting which reportedly "changed his course", according to Cheatsheet.

The rest is history, Mark Harmon became a familiar face on television, he has appeared in several shows and films since then, including St. Elsewhere, Flamingo Road, and Reasonable Doubts. He has been portraying "Leroy Jethro" in NCIS since 2003, which is probably the role that most fans relate to when they hear his name!