After a postdoc position in the laboratory of Renato Dulbecco, Puck was recruited in 1948 to establish and chair the University of Colorado Medical School's department of biophysics.
Confirming research done in 1956 by Joe Hin Tjio, Puck's team found that humans had 46 chromosomes rather than 48 which had earlier been believed.
Derived CHO cell lines became the most productive manufacturing approach for therapeutic proteins, resulting in hundreds of highly efficient drugs.
Puck has won a number of honors for his work most notably the Albert Lasker Award for Basic Medical Research in 1958.
A member of the National Academy of Sciences since 1960, Puck published more than 200 papers on topics including Alzheimer's disease and Down syndrome, and optimising radiotherapy dosages for the treatment of cancer.