In a video posted to YouTube, Maezawa visited a Tokyo bank to update his bank book, which showed a new balance of around 100 billion yen ($900 million).
"It's nerve-wracking!" Maezawa said as he entered the branch.
The windfall follows a tender offer by Z Holdings, which is controlled by SoftBank's domestic wireless unit, for half of Zozo's shares this month.
The deal saw Maezawa reduce his stake in the fashion company to 18%.
Maezawa made 150 billion yen in the deal but a third has already been used to pay down debt, he said in the Youtube video from the seat of his chauffeur-driven car.
The former punk band drummer is well-known for his love of high-end art and sports cars.
Maezawa, who has a close relationship with SoftBank founder Masayoshi Son and is planning a trip around the moon in a rocket from Elon Musk's SpaceX, stepped down as Zozo CEO following a series of botched initiatives.
His stake sale is the latest pay-out by SoftBank to a wealthy company founder.
In September the investment conglomerate bailed out office-sharing startup WeWork in a deal that saw co-founder Adam Neumann exit with a $1.7 billion package.
(Reporting by Sam Nussey; editing by Jason Neely)
By Sam Nussey