Speaking to a sea of colorful Class Day hats, Theo Epstein ’95 — the baseball executive who led the Chicago Cubs to the 2016 World Series — urged the graduating seniors in the class of 2017 to defy convention and engage with their communities.

Epstein, this year’s Class Day speaker, told the story of the Cubs’ epic extra-innings victory over the Cleveland Indians in Game 7 of the World Series last November, stressing the importance of opening oneself to others. Although the Cubs won the game and ended a 108-year championship drought, the team’s greatest accomplishment, Epstein said, was not its triumph on the scoreboard but its unity in the locker room.

“Even though so much can be quantified these days, the most important things cannot be,” Epstein said. “When things go really, really wrong, and then when it rains on top of everything else, I ask you to choose to keep your heads up and come together.”

As he opened his Sunday afternoon address, Epstein also pointedly thanked Yale’s “great graduate student teaching assistants,” in an apparent reference to the graduate students who are currently battling the University for union recognition. Local 33, Yale’s graduate student union, is planning a major demonstration during Commencement Day tomorrow morning.

But on Sunday, after a few subtle criticisms of President Donald Trump, Epstein focused more on baseball than on politics. He recounted the difficulty of his first season as president of baseball operations for the Cubs, in which the team suffered more than a hundred defeats. And he recalled a locker-room exchange during a rain delay near the end of Game 7 in which Cubs players rallied around each other rather than retreat into their shells.

“We were winners that night in Cleveland, because when things went really, really wrong our players knew each other so well that they could come together,” he said. “They trusted each other so much that they could open up and be vulnerable.”

A former sports editor for the News, Epstein became the youngest general manager in baseball history when he joined the Boston Red Sox in 2002 at the age of just 28. Two years later, he vaulted into the national spotlight after leading the Red Sox to the team’s first championship in 86 years, breaking the Curse of the Bambino. In 2011, Epstein joined the Cubs, a long-struggling franchise that had gone more than a century without winning the World Series, having just secured a second championship with the Red Sox.

Later in the Class Day ceremony, Yale College Dean Jonathan Holloway, Athletics Director Tom Beckett and Head of Pierson College Stephen Davis presented nine awards to 11 high-achieving seniors, for everything from academic accomplishment to athletic prowess. Among other award winners, Richard McCoy ’17 won the Alpheus Henry Snow Prize for his achievements as a linguistics major, while Alexandra Barlowe ’17 and Abdul-Razak Zachariah ’17 received the Nakanishi Prize for enhancing race and ethnic relations at Yale.

In a performance described in the program as a “surprise tribute,” Gian-Paul Bergeron ’17 dedicated a call-and-response song to Holloway, who in just over a month will leave Yale to become the provost of Northwestern University. When Bergeron signaled, members of the audience cried “stay” and “you’re a really swell guy” to a beaming Holloway.

But the highlight of the ceremony was Epstein’s speech, which featured baseball lingo and several Yale jokes.

“That’s just an unprecedented commitment to the Saybrook Strip,” he said, referring to Yale students who were arrested for fully disrobing at the Harvard-Yale football game in November. “Back in my day, we kept our underwear on and didn’t get hauled off by Harvard police.”

After a screening of the Class Day video, in which graduating students recalled their first memories of life at Yale, the ceremony concluded with a rendition of “Bright College Years,” the traditional anthem that all undergraduates sing at their Freshman Address.

“Where’er upon life’s sea we sail,” the students sang as they waved white handkerchiefs to the sky. “For God, for Country and for Yale!”