Steve Hightower's first job was working nights and weekends for his parents' cleaning business.
While he was in college, it made sense to continue.
"I started as a janitor. I started cleaning floors and toilets and doing those things that most people would never even dream of doing," says Hightower, who appeared on CNBC's "Blue Collar Millionaires." But, he says, "I wanted more."
When he graduated from Wright State University in Dayton, Ohio, in 1978, he started his own small construction company.
As he tried to grow his business, Hightower struggled to get access to credit. At the same time, he learned about a program to sell gas in Ohio. That gave him ideas.
Hightower has always had big dreams, and he has never doubted his capability.
"When people ask me would I ever have imagined I would be where I am today? Absolutely," Hightower tells CNBC.
"Because if you don't think that you can be great, you'll never be great. And I knew that I was gonna be great a long, long time ago."
Hungry for growth and frustrated with the barriers he was encountering in construction, Hightower pivoted: He developed an oil and transport business in 1981.
At first, growth was slow there too. In 1984, he had just one employee, an accountant, and Hightower Petroleum brought in its first $100.
"I remember when our first one hundred dollar bill came in," says Hightower. "I just remember our excitement."
Today, his wholesale diesel and gasoline company, Hightowers Petroleum, has 85 employees and sells 140 million gallons of oil per year. It buys oil products from refiners and delivers it to corporate customers such as FedEx and GM all over the country. It did $350 million in 2015 and hopes to hit half a billion in 2017.
The former janitor now drives a Jaguar and lives in a 11,000-square-foot mansion decorated with modern art. He also owns a stake in FC Cincinnati, a professional soccer club. He says he didn't grow up watching soccer, but, because he sees the potential to make money by being an investor, "now, I am a soccer fan."
Despite his success, Hightower says he still has aggressive growth goals.
"I still haven't made it. I'm still a very humble individual who's trying to do the best that they can and actually one day actually make it," says Hightower. "Because I understand what real money is. And the money that I'm playing with, some people use for, you know, exercise."
He says he will also always stay true to the words of wisdom his dad shared.
"The best piece of advice that I ever got was from my father," says Hightower: "'As long as you're honest, and as long as you don't try to beat anyone, and you do the right thing, then you have the ability to be successful.' And that I think is the best advice that I've had and that I can give to anybody else."