The only solid reason that given for Mark Harmon to sport a mustache on NCIS, YEARS AGO, was that the desire was to make his character, Leroy Jethro Gibbs, look a little rougher and give the impression that he was a bit scruffier. One has to remember that at the time Gibbs had retired from NCIS and was living in Mexico with his buddy and former mentor, Mike Franks, played by Muse Watson. He was sporting a rough beard at one point to show that he was more or less unrestrained and having a good time during his retirement, meaning he’d learned how to kick back and simply let things go. Once he returned to the fold though he did shave off most of his facial hair, but for some reason, he kept the mustache. It was an odd choice, to say the least since it didn’t really do anything for a lot of fans, but the fact is that a lot of people, including those in charge, figured it had to go since it gave him the look of a retired cop or substitute teacher rather than the hardened leader that he was supposed to be. In fact, a few gags were made around the mustache, making it clear that the showrunner had seen or at least heard about the many comments that many fans had made concerning the facial hair faux pas. If the point wasn’t already made, a lot of people wanted to see Gibbs clean-shaven and likely with the high and tight haircut that he’d been sporting since the beginning of the show. Yes, people put this much emphasis on looks instead of just character, and while they might be right sometimes, a lot of folks make it necessary to shake your head and just move on.
Gibbs has been such a mainstay of the show that anytime it might appear that he’s heading out and getting ready to hit the retirement road for good it becomes a panicky time for a lot of fans since he’s been the backbone of NCIS for a long time now and it’s not certain whether any of the others on the cast could possibly take over and do what he does. The fact is that his character is a very stern but fair individual, most times, and his background has helped him to be one of the more stable characters of the bunch while the others have been great over the years but haven’t really shown that they can take the team and do what Gibbs does. The characters that might have been able to do what he’s done for so long have moved on as Michael Weatherly and Cote de Pablo were probably two of the most likely candidates to take over for Harmon’s character, as Sean Murray, aka McGee, is a great character, but he’s not really the same caliber as Gibbs. There have been rumors of Harmon retiring eventually, but it does feel as though the show will need to take a drastically new direction or simply call it quits if that happens, and it’s very likely that we might not see every actor on the show bounce back so quickly since while they’ve all had successful careers leading up to this point, it’s safe to say that NCIS has claimed a good deal of their time over the years and it’s possible that even with the development of various characters that NCIS couldn’t really take the loss of Harmon. It would be an interesting theory to test no doubt, but at the moment it does feel as though everyone involved might rather see what can happen as they continue forward on the same course they’ve been traversing for a while.
It’s true that Gibbs’ facial hair is a little off-putting simply because it doesn’t appear to fit the character, at least not when he’s on the job. When he was retired for a short period of time it did fit in a big way since it was nice to see Gibbs relaxing and taking time to himself in order to unwind from the job. But if anyone was to comment on the character in a meaningful way they might admit that Gibbs is the kind of character that appears to need the job in order to keep himself on the level, as it’s all he really has left apart from hobbies he has and the relationships he chooses to pursue. For so many years now he’s been the work-oriented type that doesn’t do much other than work on his boats, do his job, and drink coffee. Everything else is kind of extra and tends to be seen as either an annoyance or as something that he can’t avoid. But focusing on his mustache was kind of silly even when it happened the first time.