At first it was said that agent Gibbs drinks bourbon and in a later episode he said it was "Gentleman Jack".
NCIS’s Senior Field Agent, Leroy Jethro Gibbs is addicted to caffeine and is rarely seen without a styrofoam cup of strong, black coffee in his hands.
One of the best ways to get on the wrong side of Gibbs is to 'mess' with his coffee. Off-duty he drinks either once again strong, black coffee or high-proofed bourbon, referred to once by Tobias Fornell as ‘paint stripper’.
Read more about Leroy Jethro Gibbs here.
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