Mark Harmon's highly-anticipated return for the NCIS: Origins crossover episode came as a surprise for some viewers following his shocking exit. During the Tuesday, November 11, double feature, Harmon, 74, reprised his role as Gibbs in the opening scene of the prequel, where a present-day version of the character reflected on his life while in a cabin with a dog. "Three decades, it's a hell of a long time. That's how long I put in on the job. Lately, I've been thinking a lot about those early days," he reflected. "Back when I was still cutting my teeth.