The song plays at every Red Sox home game, in the middle of the eighth inning, with Boston fans blissfully singing along, chanting "So good! So good! So good!" in response to the recorded Diamond marveling at the good times.
When, two weeks into the 2013 baseball season, two bombs exploded at the Boston Marathon, "Sweet Caroline" was suddenly more than just the Red Sox's anthem. It belonged to America.
At least, that's how Major League Baseball sees it.
After the bombings, the tune was played at several ballparks, most that of the Red Sox's biggest rival, the New York Yankees.
And at Tuesday's All-Star Game, Diamond came out to sing it again, performing it for the first time at the home of the Yankee's cross-town rival Mets, Citi Field.
The All-Star Game performance was intended as a tribute for Boston, but in New York, it didn't quite get the throaty sing-along it does at Fenway.
(With the exception of this guy.)
But even Neil Diamond would be hard pressed to surpass what came next, a moment when baseball paid tribute to one of the greatest of its own.
Mariano Rivera, the Yankees closer widely regarded as the best ever to play the game, took the field to pitch the bottom of the eighth.
The driving bass of "Enter Sandman," the Metallica song that has served as Rivera's entrance music since 1999, pounded through the stadium.
Players from both sides, National League and American, stood on the steps of their respective dugouts, while Rivera jogged in from the right field bullpen.
He stood on the bump, alone, for more than a minute while the stadium and players applauded him, doffing their caps in respect. He raised his hat in return, clearly moved.
Mo pitched a perfect frame, as if there were any other possibility.
While while Rivera faced down his third, and final out, another baseball great, Hall of Fame-bound announcer Tim McCarver, recited the chorus of "Enter Sandman".
And when fans voted him the game's Most Valuable Player, they didn't mean it just for the All-Star Game.
Rivera had some words of gratitude after the game: