Mark Harmon in 'NCIS: Origins' CBS Share on Facebook Share on X Share to Flipboard Send an Email Show additional share options Share on LinkedIn Share on Pinterest Share on Reddit Share on Tumblr Share on Whats App Print the Article Post a Comment Logo text Mark Harmon is making an on-screen return to the NCIS universe. Harmon will guest star in an episode of NCIS: Origins on Nov. 11, reprising his longtime character Leroy Jethro Gibbs. The episode will be part of a crossover with NCIS, following a case that spans the 1990s-set Origins and the present-day setting of the flagship series.