Hurwicz received a Guggenheim Fellowship for 1945–1946. In 1946 he became a professor of economics at Iowa State College. From January 1942 until June 1946, he was a researcher for the Cowles Commission. He worked full-time for the Cowles Commission until October 1950 until January 1951, he was a visiting professor, teaching at classes that were taught before by Professor Koopman in the Department of Economics, and he was a very important professor there. He was also a research professor of economics and statistics at the University of Illinois, a consultant to the RAND Corporation for the University of Chicago and a consultant to the U.S. government. Hurwicz continued to be a consultant to the Cowles Commission until about 1961.