BOSTON >> Juneteenth flag designer Ben Haith stood on the mound at Fenway Park before the Red Sox hosted the Yankees on Sunday, waving his arms to pump up the crowd.

A collection of Black community leaders and Red Sox employees fanned out behind him, all wearing special Juneteenth commemorative jerseys that bore Haith’s creation on the back.

“It feels like I’m living in a miracle,” Haith said before throwing a ceremonial first pitch as part of baseball’s commemoration of Juneteenth, which marks the date that news of the end of slavery reached Texas — two years after the Emancipation Proclamation. Juneteenth became a federal holiday in 2021.

“It wasn’t always comfortable for me to come to Fenway Park, because sometimes I would hear people called names,” said Haith, who designed the red and blue Juneteenth flag with the exploding white star that was first raised in the Boston neighborhood of Roxbury in 1979. “But things have changed and it’s like a miracle.”

The last team in the major leagues to integrate their roster, the Red Sox were among the teams marking the June 19 holiday this weekend.

WWE announcer Samantha Irvin performed “Lift Every Voice and Sing,” known as the Black National Anthem, as well as the “Star-Spangled Banner.” On Monday, an exhibit from the Negro Leagues Baseball Museum, “Barrier Breakers: From Jackie to Pumpsie,” will open at nearby Emerson College.

“Lift Every Voice” was also performed in Oakland before the Athletics’ game against the Phillies. The Mariners celebrated Juneteenth on Saturday with “Salute to the Negro Leagues” day, wearing jerseys from the Seattle Steelheads from the 1940s.

In Washington, the Nationals will mark the occasion on Monday with a special matinee start for their series opener against St. Louis. Fans buying a special ticket package received a Nationals Juneteenth T-shirt, and $5 from each of those sales will be donated to the National Museum of African American History and Culture.

The occasion was especially poignant for Haith, who learned about Juneteenth while growing up in Virginia. (His aunt’s husband was named June — “the name stuck with me,” Haith said.) He lived for a time in Connecticut and followed the Yankees, Dodgers and Giants, and after moving to Boston never felt the pull of the Red Sox.

Haith had heard the stories about how the Red Sox gave Jackie Robinson a sham tryout and also opted not to sign Willie Mays. The ballclub did not field a Black player until Pumpsie Green in 1959 — more than a dozen years after Robinson broke baseball’s color barrier.

Former Boston Mayor Kim Janey, who was the first woman and the first person of color to hold the office, said the team has come far since then.

“I’ve been so impressed with the Red Sox organization and everything that they are trying to do to really make sure that there’s healing in our city, to make sure that we are righting wrongs of the past,” said Janey, who also took part in the pregame ceremony. “It’s wonderful to see, and we need to do more of it.”