Quin has invested in a variety of start-ups, including Health Warrior, PeerWell, and pawTree. In terms of choosing which companies to get involved in, it's always been about "finding something that we loved, something that we wanted to do, and something that we wanted to be a part of," Quin tells CNBC.
He's also invested in fantasy sports tech companies FanDuel and DraftKings, which recently agreed to merge. "I think that's a great move," he says of the merger. "They're two great companies that bring something to sports that the fans loves."
In addition to private equity investments, the NFL star puts some of his money into the stock market, he tells CNBC: "I have some stuff in stocks — long-term stuff. Safe stuff."
Quin still has a few NFL seasons ahead of him, but when his career does come to an end, he'll be in good financial standing.
The plan has always been to "save as much money as I can and spend as little as I can in the time that I have in the league," Quin tells CNBC, "so that I can maximize my future."