First, he spoke at a $50-a-ticket buffet and presentation at Antietam Hotel & Conference Center Antietam Creek on Dual Highway.
More than 300 people attended, including about four dozen who paid $750 or $1,000 to privately get Mays' autograph beforehand.
Mays, 73, later took part in a pregame ceremony at Municipal Stadium, where tickets were a fraction of the price and the crowd was more than 10 times bigger.
It was at Municipal Stadium that Mays, at age 19, played his first professional game in the New York Giants' minor league system on June 24, 1950.
Mays and people at that game have said that some fans yelled racial epithets and other derogatory names at him. He was forced to stay at the all-black Harmon Hotel on Jonathan Street, apart from his white teammates.
In a 1988 television interview, Mays said Hagerstown was where he suffered the worst treatment when he broke into baseball.
"In 1950, when I was here, it was such a sad, you know, moment," Mays told Monday's stadium crowd, "but, still, everything works out. ... I have no regrets coming back."
At the hotel reception, Mays said he turned down an invitation three or four years ago to be a parade grand marshal in Hagerstown.
"I declined," he said, "because I had a little sadness in my throat. (But) I said to myself, 'No, that's not the way to go.'"
"Hagerstown has made a lot of strides and came forward 'cause we're all here to ... welcome you to the community where you started your career with the New York Giants," said Hagerstown Mayor William M. Breichner, who was at Mays' first game.
"And I can honestly say that, you know, it was very unfortunate, what happened. ... I guess, that was a trend in those days, but it's no excuse for that sort of thing happening to any individual."
This time, Mays was treated like royalty. Fans cheered heartily and gave him standing ovations at the hotel and the stadium.
The Suns retired his uniform number. The city added his name to a stretch of East Memorial Boulevard that runs by the stadium. Brian Robinson, whose great-grandfather owned the Harmon Hotel, gave Mays a plaque.
Kurt Landes, the Suns' general manager who arranged the event, including paying Mays' fee, said Mays' return was magical.
"Words can't describe for myself and ... the Hagerstown Suns how proud we are to have Willie Mays with us tonight here in Hagerstown," he said.
Exuberant fans agreed.
Robert Perrott, 53, of Hagerstown, brought his grandson, Ryan Bean, 13, to the hotel and waited for Mays to arrive in a white stretch limousine. Perrott said Mays is probably "number three in my book" behind Babe Ruth and Hank Aaron.
Sean Guy, 44, of Greencastle, Pa., paid his way into the autograph session with a scorecard of Mays' first game for him to sign.
Former Major Leaguer Joe Durham, 73, of Randallstown, Md., said he played with Mays in the U.S. Army in Newport News, Va.
Among baseball stars, "there's nobody that can touch you," Durham told Mays.
Some people were disappointed Mays' schedule was tight and allowed little mingling.
Outside the stadium, Gary Harmison, 24, of Greencastle, held out his late great-grandfather's 1951 World Series program - and hoped Mays would sign it.
But Harmison gave up before Mays got into a limousine and left in the bottom of the first inning.
Harmison wondered why Mays - whose typical appearance fee ranges from $30,001 to $50,000 - didn't interact more with fans.
"He has his money," Harmison said. "He's a big-name guy. (Why not) just make somebody smile?"
Les Files, 47, of Halfway, watched as his daughter, Casie, 8, waited to hand Mays a bag of Cracker Jack. Casie had drawn welcome signs with messages such as "Welcome Mr. Mays Say Hey Hey" and "Willie Mays Forever In Our Hearts."
Casie didn't get the chance, so Files followed Mays' limousine through Hagerstown and held up one of Casie's signs. He said that when he got near the limousine on Franklin Street, police ordered him to stop.