If you call Antonio Sustiel and he doesn't answer, his voicemail guarantees that he'll get back to you "within a few minutes."
It's this type of round-the-clock work ethic that has helped the grade-school dropout become a self-made millionaire. As the founder and CEO of Flooring King, Sustiel turns piles of wholesale laminate flooring into cash.
The Israeli immigrant has a true rags-to-riches story. He dropped out of school at age 10 to work for his father's construction company, and then served in the Israeli army starting at age 18.
When he landed on U.S. soil at age 23 in 1987, he had $400 in his pocket, Sustiel says on CNBC's "Blue Collar Millionaires." He moved to Florida determined to make his own American dream a reality.
Sustiel began selling cheap perfume in Miami, and over the next several years, he developed a reputation as a successful businessman. He then invested in a 5,000-square-foot warehouse, spending $690,000 for the space.
It would turn out to be the decision that would launch his career. Not long after, an acquaintance called him saying that he had 20 industrial-sized containers of laminate flooring he wanted to get rid of.
Sustiel recalls saying, "I have no idea what laminate flooring is, but I have a warehouse to store the material. And I can sell it."
Thus, in 1999 Flooring King was born.
"In the beginning, there must be a positive mental attitude," Sustiel tells CNBC, reflecting on his early success. "Wake up early in the morning. Have the right energy."
Over the past 15 years, his company has sold $40 million of flooring. In any given day, Flooring King does 10 to 15 houses per day. His business model is to buy wholesale laminate flooring that other manufacturers don't want anymore and sell it at a higher price than he paid.
The entrepreneur has never been afraid to get his hands dirty. He still loads trucks himself and visits work sites with his employees.
It took a few decades, but Sustiel's hard work paid off. Now he's reaping the rewards. He lives in a mansion in Ft. Lauderdale and owns a Ferrari, Bentley, Tesla and Rolls-Royce.
The self-made millionaire says that one trick in particular has helped him land more opportunities: Always being available by phone.
He might be at a party or at home getting ready for bed, he explains, but if the phone rings, his policy is to make every effort to answer.
"Work hard," Sustiel says. "If you don't put in 15 to 20 hours of work each day, you're never going to make it big. Put the business first."