1940 - He published a prominent physics textbook, The Modern Theory of Solids.
1949 - He served as a professor of physics at the University of Illinois.
1962 - He served as the president of the National Academy of Sciences.
1968 - He was president of Rockefeller University.
1979 - His retirement from Rockefeller University, Seitz began working as a paid permanent consultant for the R.J. Reynolds Tobacco Company, advising their research program.
1989 - The CEO of R.J. Reynolds, William Hobbs, concluded that "Dr. Seitz is quite elderly and not sufficiently rational to offer advice.
1994 - Seitz authored a report published by the George C. Marshall Institute, of which he was a founder and chairman of the board, entitled "Global warming and ozone hole controversies.