First baseman Pete Alonso smashed a rookie-record 53 home runs, clicked with a city and its fans well beyond simply blasting moonshots, coined a slogan or two and perhaps inspired a comedy genius to reboot a classic sitcom.

Oh, and the 24-year-old also infused the Mets' clubhouse with a sincere, caring spirit, mauled the club’s record book, made the All-Star Game, won the Home Run Derby, showed the scouting community he had been underestimated, bolstered his defense at first base and became the "Polar Bear.”

What a first season for Alonso, the unanimous selection as the Baseball America Rookie of the Year.

"I couldn’t have asked for a better rookie year,” Alonso said. "This is a fantasy come true.”

The reality, though, took hard work, scouting, player development and the guts to make a difficult decision. First-year Mets general manager Brodie Van Wagenen could have kept Alonso at Triple-A in April to retain an extra year of contractual control in 2025, but instead he carried Alonso on the Opening Day roster when it was obvious he had won the first base job in spring training.

The rest is Mets—and now baseball—history.

"Pete had an extraordinary season,” Van Wagenen said. "More importantly, he demonstrated tremendous worth ethic and rare leadership qualities for a young player. He genuinely prioritized winning games over his historic personal pursuits. He was a big part of our team’s success in 2019 and he is part of a talented core that will impact the Mets for years to come.”

Alonso, who turns 25 in December, started the season ranked as the No. 48 prospect in baseball, a power hitter with a perhaps suspect glove. But he led the major leagues in home runs, finished third with 348 total bases, tied for third with 85 extra-base hits and was fourth with 120 RBIs.

Along the way, he became the first rookie and the first Mets player to lead the majors in home runs. There was still more than a month left when he broke the club record for homers, 41, which had been shared by Carlos Beltran and Todd Hundley.

And on the second to last day of the season, Alonso broke Aaron Judge’s major league rookie record for homers. Tears sprang to Alonso’s eyes when he took the field for the following half-inning.

"To be part of Major League Baseball history, to be No. 1 out of every single guy to play the game, it’s humbling and it’s such a ridiculously awesome feeling,” Alonso said. "That moment was pure magic.”

By that time, Mets fans had been all-in on Alonso for months. Members of the 1969 Mets, who were around the team all season for 50th anniversary celebrations of the World Series champions, also fell for the "Polar Bear,” as Alonso was dubbed by teammate Todd Frazier.

It wasn’t just the home runs. Alonso has a knack for connecting. He posted a workout video to YouTube when he was a minor leaguer—complete with an ’80s rock soundtrack—and was clearly delighted to show fans how ballplayers train.

To Jon Updike, the scout who signed him in 2016 after the Mets drafted him out of Florida in the second round, that video is Alonso showing "that’s he’s a genuine human being. That’s just who he is.”

Last July, Alonso tweeted a message to Mets fans, urging them to support a team on the rise. "The boys are hot,” the tweet read, in part. At the end, the phrasemaker added a hashtag that rocketed straight into Mets lore: #LFGM. Fans loved it as much as they loved an Alonso exit-velocity binge.

He played along with popular storylines, too. When the idea of he and Judge going out to dinner came up, Alonso suggested if he were paying, they’d hit McDonald’s. If Judge were picking up the check? Peter Luger’s, the famed Brooklyn steakhouse.

Late in the year, Jerry Seinfeld, a rabid Mets fan, suggested on social media that he would revive "Seinfeld” if he could get Alonso to play a role like Keith Hernandez did in the famous two-part episode "The Boyfriend" from 1992.

Alonso also touched New York City’s soul on the 18th anniversary of the Sept. 11 terror attacks. Alonso ordered cleats—painted red, white and blue with the words "never forget”—for his teammates to wear in the game that night.

"I want to show support, not just to the victims, but the families as well,” Alonso said. "No one really knows how deep those emotional scars can be.”

Alonso donated part of the $1 million he earned for winning the Home Run Derby—$50,000 to the Wounded Warrior Project and $50,000 to Tunnel to Towers, a foundation dedicated to first responders.

"He’s making the minimum. He could’ve said, ‘Let me put that in my pocket, squirrel that away,’ ” said native New Yorker Ed Kranepool, a member of the ’69 Mets who forged a bond with Alonso. "That tells you where he’s coming from. He’s thinking about giving back. That’s why I have the utmost respect for this kid. I want to see him do well.

"All of New York does.”

Added Updike: "Being able to thrive in that environment, you can’t fake it. That was so cool to watch, that kid be so comfortable.”

In fact, Mets scouting director Marc Tramuta said the organization is as proud of Alonso for the way he carries himself as it is for his baseball talent. "He seems to be the one everyone gravitates to,” Tramuta said.

Even before the decision was made to give Alonso first base, it was clear the Mets thought the world of him. When Van Wagenen took over, he famously had dinner with Alonso and told him, yes, he really could make the team.

Allard Baird, the Mets’ vice president and assistant general manager recalls his inbox filling with workout videos from Alonso during the offseason. "He showed us before he came into camp what he was working on,” Baird said. "He was truly on a mission.”

So was Van Wagenen. When Alonso proved he was good enough, the GM did not hesitate to put him on the roster, saying at the time he would not sacrifice "the best product for the fans and the best product for the other 24 guys in that clubhouse to save service time or potential future money six years down the road.”

Alonso had certainly put in the work. Ian Levin, the Mets' senior director of baseball operations, remembers Alonso’s max-effort style dating back to instructional league following his pro debut in 2016.

"Doing drills, it could be half-moons (fielding drills) and he’s the leader each time, busting it,” Levin said. "That’s just a microcosm of what he gave. He never did anything without his best effort.”

No wonder Alonso was able to spike one storyline that threatened to follow him into the season. Alonso was not considered a quality defender at first base, but he worked at his craft. "He was not the plumber people thought he was going to be,” Kranepool said. "He worked his way into being a good first baseman.”

"That’s a credit to (Gary) DiSarcina (the Mets’ third base coach) and (Tim) Teufel (the organization’s infield coordinator) and our player development people,” Tramuta said.

Still, there was some doubt about Alonso overall potential, even with his power, which Updike describes as "magical. It’s what fills the stands in our game.”

But righthanded-hitting, righthanded-throwing first basemen tend to be underappreciated. Alonso’s prospect ratings certainly didn’t foreshadow his historic rookie season. In spring training, Baseball America quoted a scout who questioned Alonso’s hitting prowess and even said he "can’t recall him ever hitting a slider.”

Alonso clearly relished the vindication his season has brought: "(Scouts) also said I couldn’t hit a slider,” Alonso said. "That is cool how the tables have turned.”

The whole season was cool, worthy of BA’s Rookie of the Year.

"This felt good,” Updike said. "I’m the guy who wrote the report and pressed the button, but it was a team effort, not only scouting, from player development, the big league staff and the front office, the way they approached it. Brodie did a tremendous job of putting him in a position to have success at the right time.

"And Pete’s taken advantage of it. It’s amazing what can happen when you get the opportunity. Now it’s his to run with the rest of his career.”

Anthony McCarron is a freelancer based in New York

Mets correspondent Mike Puma contributed to this story