Kálmán worked as a Research Mathematician at the Research Institute for Advanced Studies in Baltimore, Maryland from 1958 until 1964. He was a professor at Stanford University from 1964 until 1971, and then a Graduate Research Professor and the Director of the Center for Mathematical System Theory, at the University of Florida from 1971 until 1992. He periodically returned to Fontainebleau from 1969 to 1972 at MINES ParisTech where he served as scientific advisor for Centre de recherches en automatique. Starting in 1973, he also held the chair of Mathematical System Theory at the Swiss Federal Institute of Technology in Zürich, Switzerland.