After earning a B.A. at Hillsdale College in 2001, Leeson entered the Ph.D. program in economics at George Mason University. After time as Visiting Fellow in Political Economy at Harvard University in 2004, he earned his doctoral degree from George Mason in 2005. Leeson completed a post-doctoral fellowship as an F.A. Hayek fellow at the London School of Economics.

After returning from London in 2005, Leeson accepted a position as an Assistant Professor of Economics at West Virginia University, where he remained for two years. In 2007, he left WVU to accept a position as BB&T Professor for the Study of Capitalism at George Mason University. He is also a Senior Scholar at GMU's Mercatus Center.

Besides his teaching and research positions at George Mason, Leeson is a Distinguished Scholar at the Center for the Study of Political Economy at Hampden-Sydney College, a Research Fellow of the Independent Institute, and serves on the Executive Committee of the Society for the Development of Austrian Economics. He is also a member of the Board of Scholars of the Virginia Institute for Public Policy, Associate Editor of the Review of Austrian Economics, and an Adjunct Scholar at the Mackinac Center for Public Policy.

Much of Leeson's research examines self-enforcing exchange and private social structures. Leeson has posed consequentialist arguments for anarcho-capitalism, asserting that,

"the case for anarchy derives its strength from empirical evidence, not theory.... Despite... significant arenas of anarchy we do not observe perpetual world war in the absence of global government, shriveling international commerce in the absence of supranational commercial law, or even deteriorating standards of living in Somalia. On the contrary, peace overwhelmingly prevails between the world’s countries, international trade is flourishing, and Somali development has improved under statelessness."

The Fund for the Study of Spontaneous Orders, which is administered by the Atlas Economic Research Foundation, awarded Leeson its Hayek Prize in 2006, noting of his scholarship that,

"Leeson has concentrated on the study of the problem of order where no formal law exists, showing how in such diverse situations as trade among strangers, banditry in colonial West Central Africa and modern Somalia, and life in pirate societies over the ages often informal rules emerge that allow order to be preserved without heavy handed government control."

Economics of piracy

In the wake of the Maersk Alabama hijacking, Leeson's book and numerous articles on the topic of piracy have drawn substantial media attention. In an article published by National Public Radio, he said that "early 18th century pirates, men like Blackbeard, "Black Bart" Roberts, and "Calico" Jack Rackam, weren't only thieves. They were also early experimenters with some of the modern world's most cherished values, such as liberty, democracy, and equality."

Although Leeson is careful to note that he does not praise the criminal actions of pirates, he argues that their self-organization is a useful illustration of how even criminal conduct is based on rational self-interest. In an interview published by The New York Times, Leeson summarized his thesis:

"The idea of the invisible hook is that pirates, though they’re criminals, are still driven by their self-interest. So they were driven to build systems of government and social structures that allowed them to better pursue their criminal ends.... The reason that the criminality is driving these structures is because they can’t rely on the state to provide those structures for them. So pirates, more than anyone else, needed to figure out some system of law and order to make it possible for them to remain together long enough to be successful at stealing."

He has a tattoo of a supply and demand curve on his right biceps.