He spent 1957-1958 studying protein chemistry in the Laboratory of Christian B. Anfinsen at the National Institutes of Health in Bethesda.
In 1977 he moved to the University of Connecticut School of Medicine to become the first chief of cardiology.
Since his retirement in 1998 he has been acting as visiting professor of Medicine and Physiology at Dartmouth Medical School.
In 2008 he was also appointed Visiting Professor of Medicine at Harvard Medical School.
[3] The American Heart Association renamed its young investigator award for basic research the Louis N. and Arnold M. Katz Prize in his honour.