after an interlude as a research physicist at General Electric Laboratories (1937–39) he was at the University of Pennsylvania (1939–1942) and then the Carnegie Institute of Technology (1942–49). From 1946 to 1947, Seitz was director of the training program in atomic energy at Oak Ridge National Laboratory. He was appointed Professor of physics at the University of Illinois, Urbana-Champaign, in 1949, becoming chairman of the department in 1957 and dean and vice-president for research in 1964. Seitz also served as an advisor to NATO. From 1962 to 1969 Seitz served as president of the United States National Academy of Sciences (NAS), in a full-time capacity from 1965. As NAS president he initiated the Universities Research Association, which contracted with the Atomic Energy Commission to construct the world's largest particle accelerator at the time, Fermilab. He was the president of Rockefeller University from 1968 to 1978 during which he helped to launch new research programs in molecular biology, cell biology, and neuroscience as well as creating a joint MD-PhD program with Cornell University. He retired from Rockefeller University in 1979, when he was made President Emeritus. Consultancy career After Seitz published a paper on the darkening of crystals, DuPont asked him in 1939 for help with a problem they were having with the stability of chrome yellow. He became "deeply involved" in their research efforts. Among other things, he investigated the possible use of non-toxic silicon carbide as a white pigment. Seitz was a director of Texas Instruments (1971–1982) and of Akzona Corporation (1973–1982). Shortly before his 1979 retirement from Rockefeller University, Seitz began working as a permanent consultant for the R.J. Reynolds Tobacco Company, advising their medical research program until 1988. Reynolds had previously provided "very generous" support for biomedical work at Rockefeller. Seitz later wrote that "The money was all spent on basic science, medical science," and pointed to Reynolds-funded research on mad cow disease and tuberculosis. Nonetheless, later academic studies of tobacco industry influence concluded that Seitz, who helped allocate $45m of Reynolds' research funding, "played a key role... in helping the tobacco industry produce uncertainty concerning the health impacts of smoking." According to a tobacco industry memo from 1989, Seitz was described by an employee of Philip Morris International as "quite elderly and not sufficiently rational to offer advice." In 1984 Seitz was the founding chairman of the George C. Marshall Institute, and was its chairman until