The former NY Giants superstar was formally introduced as one of the club's newest minority owners on Wednesday ... alongside current Giants exec Pete Guelli, who's also taking a slice of the franchise.

Manning explained his reasoning behind the business move -- saying it made complete sense.

"I have lived and worked in this community for almost two decades," said Manning, who played his entire career with the G Men. "It's home to me, and Gotham FC is my family's favorite soccer club."

"Combine that with the organization's strong leadership, talented roster, and sustained growth, and it became clear that joining this great group was a fantastic opportunity."

Gotham FC chair Tammy Murphy is excited about bringing Manning on board ... saying, "Eli is known for the positive and influential impact he has on our communities."

"His legendary work ethic, drive for success, and passion for giving back to the community will be tremendous assets for our club."

Gotham FC exec Ed Nalbandian also lauded the new additions ... saying, "Having two people with track records like Eli and Pete recognize the value of our club and the strength of our brand speaks volumes about Gotham FC's upward trajectory."

"Their investment, influence, and additional resources will allow us to be even more successful on and off the field."

Manning and Guelli join big names like Kevin Durant and Carli Lloyd ... who also recently joined the ownership group.

Manning -- who spent 16 seasons with the Giants -- retired from the NFL after the 2019 season, but it's clear Eli still has a soft spot for the area.