Billionaire investor Leon Cooperman: I made my fortune thanks to luck and common sense

After a successful 25-year career at Goldman Sachs, billionaire investor Leon Cooperman left to start his own hedge fund, Omega Advisors, in 1991.

Today, his firm manages approximately $3.4 billion in assets. But the Wall Street legend wasn't born rich: His parents were working-class Polish immigrants and he grew up in a one-bedroom apartment in the South Bronx.

"Whatever success I've achieved, I think I've achieved it because I've been very lucky, I have common sense and I have a strong work ethic," Cooperman said on CNBC's "Fast Money Halftime Report."

The self-made billionaire is the first to admit that he wouldn't be where he is today without a bit of luck. And he isn't the only successful business titan to do so: His good friend Warren Buffett says the key to his success has been luck, too. Buffett often says he was fortunate to win the "ovarian lottery," meaning that he was born with real advantages that helped him get ahead.

Cooperman, who is renowned on Wall Street for his value investing, also says that basic common sense has yielded great results — and not just for him: "Everyone I know that has accumulated wealth — whether it's Warren Buffett, Ken Langone, Mario Gabelli — I think they made their fortunes out of buying weakness and selling strength. … I don't get the process of buying strength and selling weakness. That's not how you make money. You buy weakness and you sell strength. That's the way to make money in the market."

Cooperman added that hard work also contributed to his success, and his friends agree. Robert Salomon Jr., who has been friends with Cooperman since the late 1960s and was an early investor in Omega, told CNBC in 2014: "Lee is the hardest working guy in the investment business I know and have ever known. I don't think he puts in long hours, I think he works around the clock. I don't care whether he's on a plane or car or in Florida presumably on vacation — he's working."

Another friend and former employee, Doug Kass, told CNBC: "He's the James Brown of hedge funds — the hardest working man in the industry."

His hard work, mixed with luck and common sense, has paid off: Today, Cooperman's personal fortune is estimated to be $3.2 billion.

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