Yeah, everybody remembers he ended the Cuban Missile Crisis.
Of course, the better lesson is that he caused the Cuban Missile Crisis. There wasn't any inherent reason the US couldn't have tried to privately negotiate their removal first, with the trade of removing US missiles in Turkey and Italy that actually happened anyway, rather than making a big public crisis and sending out the navy to confront the Russians and whatnot.
But, then, that's a sober analysis leaning on the fact that the missiles in Cuba didn't seriously increase the threat level to the US as a whole anyway; long-range Soviet missiles and Soviet missile subs already existed, after all. The real issue with the missiles in Cuba was that they combined short flight-times with reasonable accuracy, so that existing plans to evacuate the Top Men from DC in case of a nuclear war were no longer reliable. So the Top Men in DC panicked now that their safety was in danger, and they acted completely irrationally.
The correct response to the CMC would have been for the American public to form a mob and take Kennedy and his NSC and hang them from lampposts for almost starting a nuclear war in a panic. Instead, Kennedy gets all sorts of hosannas because when he pushed us to the brink by performing acts of war against the Soviets and Cubans, Khrushchev was calm and sober enough not to push us over. Khrushchev paid for that world-saving statesmanship, of course; it made the Soviets look weak, which was a major reason he was removed from power a couple years later.