Mundell has been an adviser to a number of international agencies and organizations, including the United Nations, the IMF, the World Bank, the European Commission, and several governments in Latin America and Europe, the Federal Reserve Board, the US Treasury and the Government of Canada. In 1970, he was a consultant to the Monetary Committee of the European Economic Commission, and in 1972-1973 a member of its Study Group on Economic and Monetary Union in Europe.

Mundell prepared one of the first plans for a common currency in Europe and is known as the father of the theory of optimum currency areas. He was a pioneer of the theory of the monetary and fiscal policy mix, the theory of inflation and interest and growth, the monetary approach to the balance of payments, and the co-founder of supply-side economics.

In 1999 he was awarded the Nobel Prize in Economics "for his analysis of monetary and fiscal policy under different exchange rate regimes and his analysis of optimum currency areas". His research, says the press release of the Royal Swedish Academy of Sciences, "has had such a far reaching and lasting impact because it combines formal - but still accessible - analysis, intuitive interpretation and results with immediate policy application".

The author of numerous works and articles on economic theory of international economics, Mundell has also written extensively on the history of the international monetary system. His writings include over a hundred articles in scientific journals and several books. He has received a number of international awards, including the Guggenheim Prize (1971), the Jacques Rueff Medal and Prize (1983) and the Distinguished Fellow Award from the American Economic Association (1997).