When it happened, his mother imparted a few words of wisdom about parents teaching their children the value of work. "My mother said to me, 'The dead bird under the nest is the one that never learned how to fly,'" O'Leary tells CNBC Make It.
"Mom, that is a great poem, but I need some money," he says he replied.
But his days living on her dime were over. "You're not going to get any, so you're going to fly or you're going to be dead bird," she answered.
"Woah, no dead bird for me," O'Leary decided.
Today he presides over a multitude of companies bearing his last name: wine business O'Leary Fine Wines, financial company O'Shares Investments and private equity firm O'Leary Ventures. He's also famous as a judge on ABC's "Shark Tank," through which he's invested in businesses like Plated — a meal delivery company that sold to Albertson's for $300 million. O'Leary says it was the largest exit in the history of the show.