The Dons are hoping to raise £7m – the maximum legally allowed to be raised from crowdfunding.
Wimbledon’s North Stand was renamed The John Green Stand after the American agreed a sponsorship deal in July 2015.
“I’m very proud to be able to contribute to this extraordinary club’s next chapter,” said Green.
“This isn’t solely about building a new stadium. This is something far more symbolic, a message to football that true supporters are capable of great things. Together, they can move mountains.”
Dons chief executive Joe Palmer said: “Our fans have always been there for this club whenever it really mattered.
“We mustn’t ease off, though. The more we can raise, the less we will have to borrow to pay for the new stadium – it’s as simple as that.”