Milton Friedman changed the world. How did this small man make such big changes? The answer lies as much in his story as it does in his solutions.

After Milton Friedman’s death on November 16, 2006, the diminutive intellectual cast such a long shadow that even as staunch an adversary as Paul Krugman begrudgingly remembered him as “a man of intellectual courage who was one of the most important economic thinkers of all time, and possibly the most brilliant communicator of economic ideas to the public that ever lived.” But upon his birth to immigrant parents 100 years ago today, the chances of Friedman’s becoming an academic, let alone one of the century’s most influential, seemed remote. And yet it’s Friedman’s obscure beginnings—not the months he spent on the bestseller list in 1980 or the day in 1976 when he shook hands in Stockholm with the King of Sweden—that best explain his impact.

Milton Friedman changed the world. The University of Chicago professor touted floating exchange rates, an end to wage-and-price controls, legalization of private gold ownership, dramatic tax reductions, and an end to conscription. And all of these things came to pass. Friedman the monetarist warned in the 1960s of “inflationary recessions” and rejected a tradeoff between inflation and unemployment presumed by the Phillips Curve. Fellow economists laughed at him before the 1970s laughed at them. Fledgling market economies from Europe to South America to Asia relied on Friedman as a guide.

How did this small man make such big changes? The answer lies as much in his story as it does in his solutions.

Friedman’s economics worked because he had worked. Friedman explained to fellow economists in the 1950s that “theory is to be judged by its predictive power for the class of phenomena which it is intended to ‘explain.’” He rejected ideas that worked in smart men’s heads but failed in working men’s lives.