John turned $40 worth of cloth into a $6 billion urban clothing brand, FUBU. And as he was building the company, he was living off his job as a waiter at Red Lobster. As FUBU started to grow, he spent more hours working on his business and less on his job as a waiter.

“I was working at Red Lobster for five years as a waiter as I was running this business,” John says. At first “it was 40 hours at Red Lobster and six hours at FUBU. Then it was 30 hours at Red Lobster and 20 hours at FUBU, because money started to come in.”

John’s advice to entrepreneurs is to not quit their day job. Having a second source of revenue outside your entrepreneurial venture keeps you out of devastating debt if the business doesn’t take off, he says.

Building a successful business while maintaining your side hustle will keep you busy, but that’s the price of success, says John. “Work. Bust your butt. Get up before everybody, go to sleep after everybody, and bust your butt. That’s it.”

Disclaimer: CNBC owns the exclusive off-network cable rights to “Shark Tank.”

See also:

Wharton’s No. 1 professor: “‘Never give up’ is bad advice. Sometimes quitting is a virtue.”

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