French-born American economist, who won the 1983 Nobel Prize in Economics for his fundamental contribution to the theory of general equilibrium.

In 1950 Debreu joined the Cowles Commission for Research in Economics (now the Cowles Foundation for Research in Economics) at the University of Chicago, moving with the commission to Yale University in New Haven, Connecticut, in 1955. He received his doctorate in economics from the University of Paris in 1956. He later became a professor of economics (1962) and mathematics (1975) at the University of California at Berkeley, where he taught until 1991. Debreu became a U.S. citizen in 1975.

Debreu's classic monograph, Theory of Value: An Axiomatic Analysis of Economic Equilibrium, was published in 1959. In it Debreu provided the mathematical underpinnings for the phenomenon of equilibrium in supply and demand that was first articulated (as the “invisible hand” that leads self-seeking men unwittingly to aid society) by Adam Smith (Smith, Adam) in 1776. Debreu also developed methods by which to analyze the factors that influence equilibrium.

The recipient of numerous awards, Debreu was made an officer of the French Legion of Honour in 1976 and was elected a member of the National Academy of Sciences in 1977.