Star of ABC's "Shark Tank" Kevin O'Leary is famous for his financial savvy. But it wasn't always that way.
"When I was younger, I made a big mistake. I loved to play craps," O'Leary tells CNBC Make It, referring to the Las Vegas dice game, "and it was a very important lesson for me."
O'Leary vividly remembers being in Sin City when he was in his early 20s for a computer expo trade show (at the time, he was working in the computer business). He found himself in the casino playing craps — a popular game among gamblers — until the early hours of the morning. The results were devastating.
"So there I was, sitting in the casino, 2 in the morning, rolling in the craps table — and I had practically no income [then]," O'Leary says. "And I blew myself up. I ended up in debt that night, tens of thousands of dollars. And back then, that was everything."
While it was a costly mistake, what it taught O'Leary was invaluable.
"It was a very important lesson,"O'Leary recalls. "I paid it all back, it took me a long time to do it, and I never rolled the dice again." In fact, O'Leary says it was the last time he ever gambled.
"Sometimes in life it takes an extraordinary experience like that to set you straight," he adds. "I don't take chances like that anymore, ever."
O'Leary's financially reckless behavior in Vegas all those years ago is in sharp contrast to his relationship with money today. As an investor on "Shark Tank," he's careful with his money, and he constantly preaches the importance of saving, investing and paying down debt.
"I love money," O'Leary says. "I get emotionally involved with it. I feel warm and fuzzy when I have lots of it."
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Disclosure: CNBC owns the exclusive off-network cable rights to "Shark Tank."