Friedman died of heart failure after being taken to a hospital near his home in San Francisco. His wife, Rose Friedman, survives him.
Awarded the Nobel Prize in economics in 1976 for his scholarship underlining the importance of money in determining economic health, Friedman championed the vitality of the individual over what he saw as the suffocating tendencies of the state.
His work was often seen as the definitive foil to the views of John Maynard Keynes, the British socialist whose economic theories influenced New Deal theoreticians of the Franklin Roosevelt administration and Europe's Social Democrats.
"Historical evidence speaks with a single voice on the relation between political freedom and a free market," Friedman wrote in his 1962 book, "Capitalism and Freedom."
"I know of no example in time or place of a society that has been marked by a large measure of political freedom and that has not also used something comparable to a free market to organize the bulk of economic activity."