Having initially studied mathematics, Koopmans obtained his MSc in theoretical physics from U Utrecht in 1933 and his PhD in the emerging area of econometrics from U Leiden in 1936. In 1940 Koopmans moved to Washington, working as a statistician. He joined U Chicago in 1944 and then, in 1955, Yale U. He was awarded the Nobel Prize in Economics in 1975.

http://www.nobelprize.org/nobel_prizes/economics/laureates/1975/koopmans-autobio.html Autobiography and photograph.