"He represented all of us," Jackson said. "I really feel he represented black and white."
Newcombe and former Los Angeles star Tommy Davis threw out ceremonial first pitches at Dodger Stadium before the game against San Diego.
Hall of Fame Dodgers announcer Vin Scully, who had missed five games because of a bad cold, returned to the broadcast booth. Scully, now 84, called Brooklyn games for more than seven years when Robinson played.
"All I want to do is think about the game and Jackie and how grateful I am to be back," Scully said.
Tweeted current Dodgers star Matt Kemp: "Thank u Jackie Robinson!!!"
In Boston, former Robinson teammate Ralph Branca threw out the ceremonial ball before Tampa Bay played Boston. The 86-year-old Branca tossed the pitch on one bounce from the front edge of the mound to his son-in-law, Red Sox manager Bobby Valentine.
Branca remembered being at Ebbets Field a day before Robinson's debut.
"I was in the locker room when Jackie walked in. I walked over, shook his hand, 'Welcome aboard,'" Branca said.
"I didn't think about the color of his skin because I lived on a block that was the United Nations of all. It was four black families, about nine families (of) Italian extraction, two Irish, two German, two Jewish. So it was a league of nations on my block. So blacks, I played with them, went in their house, they came into mine. So seeing Jackie meant nothing special or different to me," he said.
At Safeco Field, Russell bounced his first pitch to Seattle's Chone Figgins before the Mariners hosted Oakland. At Turner Field, Robinson's grandson, Jesse Sims, was on the field with Atlanta outfielder Michael Bourn before Milwaukee visited Atlanta. At Citizens Bank Park, Harold Gould and Mahlon Duckett of the Philadelphia Stars from the Negro Leagues were recognized, along with members of the Tuskegee Airmen.
At Kansas City, Cleveland manager Manny Acta said it was a special day.
"It has a lot of meaning to me. Those guys opened the way for everyone else. Jackie and Larry Doby, Frank Robinson was the first African-American manager. And Felipe Alou, Tony Perez. It was tough for those guys, even tougher for guys like us, minorities and foreigners."
"It wasn't tough for me," the Dominican-born Acta said. "I had it made because of guys like that. Those guys had to break the ice. They did it for us."
AP Sports Writers Mike Fitzpatrick, Beth Harris, Howard Ulman, Tim Booth and Charles Odum and AP freelance writer Alan Eskew contributed to this report.