The answer is yes — but only briefly.
While Special Agent Leroy Jethro Gibbs (played by Mark Harmon) was never a regular on NCIS: Los Angeles, he does make a brief appearance during the backdoor pilot episodes titled “Legend” Parts 1 & 2 (NCIS Season 6, Episodes 22 & 23). These episodes served to introduce the NCIS: LA team before they spun off into their own series.
In those episodes, Gibbs visits the NCIS: Los Angeles Office of Special Projects, where he interacts with several key characters, including Kensi Blye, G. Callen, Sam Hanna, and Hetty Lange. These crossover moments are the only time Gibbs physically appears within the LA setting.
So while Gibbs never guest-starred on the actual NCIS: Los Angeles series after it launched, his presence helped launch it, cementing a bridge between the two teams and marking a key moment in NCIS franchise history.
✦ Fun fact: Gibbs’ appearance helped lend credibility to the LA spin-off and hinted at a deeper shared universe, something that would become a hallmark of the franchise.
