Gibbs’s rules are a recurring gag throughout his nineteen-season run on NCIS. They range from basic advice, such as “Always wear gloves at a crime scene,” to more specific points, like “Never mess with a Marine’s coffee if you want to live.” However, one of Gibbs’s most important rules is one that NCIS breaks constantly. Despite what Mark Harmon’s iconic character might say, breaking this rule has always worked out well for the NCIS series, resulting in some of its best episodes.
Rule #10 Tells Agents Never to Get Personally Involved in a Case

Agent Gibbs’s most important rule is also one of the toughest to follow. Rule #10 forbids any agent from getting personally involved in a case. It is always a bad idea for a federal investigator to get wrapped up in the emotions and personalities of an active case. It unfailingly leads to unsatisfactory results, where agents could get hurt, or the investigation could go awry. Regardless of one’s reasoning, getting personally involved never goes well.
Gibbs first reveals Rule #10 in the Season 7 episode “Obsession,” where he admits that it is the hardest for him to follow. This also appears to be the case for (Very) Special Agent Anthony DiNozzo, who admits to having broken the rule multiple times over the years. In this particular case, getting personally involved included DiNozzo forming a relationship with a victim’s sister. Naturally, things get messy when the sister becomes the latest victim of the unidentified murderer, pushing DiNozzo over the line in his desperate search for the perp.
From a practical standpoint, Rule #10 makes perfect sense. An investigator who allows their personal emotions to get involved in a case will almost always make things messier as a result. It could even impede the investigation and get other people hurt, as was the case with DiNozzo in “Obsession.” While Rule #10 should absolutely be followed in the real world, NCIS,the series, benefits greatly from breaking the rule as often as possible. In fact, some of the crime procedurals’ best episodes are the ones that completely overlook Rule #10.
NCIS’s Best Episodes Break Gibbs’s Most Important Rule

Most of NCIS‘s best episodes are the ones that get the agents personally involved in the case. As great as it is to see the team work through cases as professionals throughout the years, the show would be nothing without the hard-hitting episodes that break Rule #10, adding a bit of extra emotional weight to the investigation.
One of NCIS‘s highest-rated episodes on IMDb is Season 6’s “Heartland,” where an investigation leads the team back to Gibbs’s hometown. Gibbs naturally becomes personally involved in the case, but audiences get to know him much better as a result. Other similarly lauded episodes include “Spinning Wheel” in Season 13 and the two-part Season 3 event, “Kill Ari,” in which the team rallies to catch a perp after they personally attack or kill one of their own. These revenge-fueled missions make for terrific television and show the emotional weight that this job takes on the characters.
These episodes bring audiences to care even more about the cast of NCIS. Getting personally involved in a case may not be professional, but it does remind the audience that the characters are still human beings. As such, they can’t help but form emotional attachments from time to time, even if it risks interfering with the case at hand. These episodes are the best in helping to flesh out the cast of the series, even if it isn’t in the most professional manner possible.
Clearly, Rule #10 is the ideal for professional investigators, but the NCIS team struggles to obey it as humans with real, raw emotions. It is for this reason that Agent Gibbs eventually decides to forego the rule altogether in Season 16. After once again finding it difficult to remain emotionally distant from a case in the episode “She,” Gibbs chooses to burn up the page containing Rule #10 in his fireplace, eliminating it from his standards forever.
NCIS is available to stream on Paramount+.