Sure, these are tough times for presidential portraits on paper money. But if you take a dollar bill out of your wallet, you'll still find George Washington's green visage at the center of it.

There's a reason for that, which goes beyond Washington's once-unassailable leadership credentials as the first U.S. president and a decorated military general. As it happens, Washington was also a savvy businessman and entrepreneur. In the recently released book, First Entrepreneur: How George Washington Built His--and the Nation's--Prosperity, author Edward Lengel, a professor at the University of Virginia, takes a deep dive into the founding father's entrepreneurial accomplishments.

Some quick history, for the uninformed: Washington used Mount Vernon to cultivate wheat (a gamble, considering everybody else was growing tobacco), transforming the estate into a regional center of production. He liked technology and installed an advanced gristmill, churning out 'G. Washington' brand flour that was even marketed overseas. Later, he took another financial risk at Mount Vernon and built a whiskey distillery, one of his most profitable enterprises.

In a recent interview with online business journal Knowledge @ Wharton, Lengel himself distilled several lessons from Washington's career. Here are five of them. 

1. Washington thought of himself as an entrepreneur and businessman, more than as a politician.  Lengel points out that when Washington became president, he said: "Building the national prosperity is my first and my only aim." 

As the director for The Papers of George Washington--a massive project analyzing and annotating Washington's many writings--Lengel has had firsthand access to the first president's business papers. These include account books, ledgers, and financial documents. "These are not just records or dreary accounts," Lengel observes in the interview. "They actually document the lifeblood of his family, his estate, and the country. It shows how much time and effort he spent on this and how important it was to him."

2. Washington's entrepreneurial sensibility made him focus on eliminating national debt and building up the nation's credit. This was no easy task: After several years of war, the U.S. owed the equivalent of "trillions of dollars" to France and the Netherlands. By his sixth year in office, Washington--with help from Alexander Hamilton--had wiped out the national debt to France. 

"He worked with Hamilton to deliver a revolving system of debt repayments to gradually pay it off through careful taxation, currency management, and by establishing a national bank," Lengel says. "Instead of wiping out the economy to pay off the whole debt all at once, he was able to manage it over a series of years, which built up the nation's credit."

3. Washington's fiscal policies created a form of national unity. He encapsulated this belief by using the phrase "communities of interest" during the Revolutionary War. His big idea was one that is still commonplace today among global trade advocates: That different nations, cultures, and interests can come together through commerce. That is, if people trade with each other, they will learn to develop and emphasize their common and shared interests--and be more peaceful as a result.

"The country could have staggered into ruin or stagnation, or it could have broken apart, both politically and physically," Lengel explains. "There was a lot of regional difference. It was an important part of Washington's national policy, tied with his economic policy, to bind the different parts of the nation together through commerce."

4. Washington's prosperity depended on his work force. Unfortunately, his workers were slaves. "Slavery can't be pushed aside as an element of his life and times," Lengel notes. "The enslaved people on his estate played a major role in building his prosperity."

And when Washington began to oppose slavery after the war, it was for fiscal reasons, rather than moral ones. "His thinking began to change with a very basic calculation," Lengel says. "He calculated that if you hold people in bondage, you restrict them from the basic right of enjoying the fruits of their own labor. Therefore, they have little motivation to work. What motivation do slaves have to innovate, invest, and think towards the future? He began to think that slavery would not only hold him back, but that it would hold the nation back in the long run."

5. Many of Washington's concepts are relevant today. Lengel believes Washington would have been an enormous advocate of the Internet, "open source" methodologies, and the gradual experimentation that informs "design" thinking. Lengel also notes that Washington's "fundamental ideas related to calculated risk taking, careful account keeping, and transparency could all be applied in the 21st century." 

What's more, Washington also had the mindset of a hacker--he believed in stealing trade secrets that private interests were protecting. "The British restricted the export of knowledge and manufacturers, and skilled labor," Lengel says. "Washington tried everything he could to bend, if not break rules, to steal industrial secrets."