Input-output analysis, or as it is sometimes called, ‘interindustry analysis’, has been put to numerous uses: to calculate the resource costs of conversion to peace-time production in 1945; to calculate the flow of trade between regions in a country; to analyse the pollutants generated by different industries in a country; and to spell out relative factor-intensities of exports and imports. Because input-output analysis deals essentially with large sets of linear equations, it lends itself naturally to the use of matrix algebra, and the widespread use of matrix algebra in modern economics is another one of the major influences of Leontief's work.

Leontief was born in St Petersburg, Russia, the son of a professor of labour economics at the University of St Petersburg. He entered his father's university at the age of fifteen and received his MA four years later in 1925. He left Russia in the same year to take a PhD at the University of Berlin. From Berlin he moved to the Institut für Weltwirtschaft in Kiel and then to Nanjing as economic adviser to the government of China. In 1931 he went to the USA as a research worker at the National Bureau of Economic Research, leaving the following year for Harvard where he remained until his retirement in 1975.

His efforts on behalf of input-output analysis have won him the French Legion of Honour in 1968, the presidency of the American Economic Association in 1970, presidency of Section F of the British Academy for the Advancement of Science in 1976, and a place in the Russian-American Hall of Fame in 1980. Throughout the 1930s, 1940s, and 1950s, he was at Harvard University.

His works include The Structure of the American Economy, 1919-1939 (1941), Input-Output Economics (1966), Essays in Economics (1966), and The Future of the World Economy (1977; with A P Carter and P Petu).