Mata is coming off a stellar season at Victory, claiming the ALM's Johnny Warren Medal with 13 assists and five goals.
The 38-year-old ace has already invested elsewhere in football and other sports, with a portfolio including MLS club San Diego FC and the BWT Alpine Formula One team.
He had previously flagged to AAP his potential interest in investing in Australian football and has now made it official, with Mata now an official long-term minority shareholder in Victory.
"Everything fell into place between me and the club since day one and I have enjoyed so much my time here so far. It's as simple as that," Mata said in a statement.
"I've seen Australian football from the inside now, and I believe in the potential of the A-Leagues.
"That's why I'm keen to be involved in what I believe will be the progression of the game in the country."
Victory did not disclose the terms of Mata's stake as Mata joins Brighton and Hove Albion owner Tony Bloom, amongst others, in Victory's ownership.
"I have great respect for what Tony has built, and I look forward to learning more about the way he works," Mata said.
Mata is currently in the United States as a pundit for the World Cup and yet to make a decision on his playing future.
He will also take up a role on a new club "football committee" when he finishes up as a player.
"I have not decided (on my future) yet. What this announcement tells you is that whatever I decide about my playing career, my long-term relationship with this club doesn't change," Mata said.
"My ownership is completely separate from my playing arrangements - different agreements, different obligations.
"While I'm playing, I'm a player and nothing more than that.
"I'm someone that wants to give their all to whatever I do, and if I continue to be a Victory player that would be my only role.
"The football committee role will begin after my playing career ends."
Mata also hopes to help more players with similar resumes - like his former teammates at Chelsea, Manchester United and elsewhere, try their luck in Australia.
"When players in Europe ask me about Australia, I tell them what I've experienced: the football is competitive, the lifestyle is incredible, and the league is only going to grow and improve," he said.
"If this announcement makes a few more of them curious - even better."
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