[1] After graduating from law school, he practiced for two years as an attorney in New York with the firm of Root, Clark, Buckner & Ballantine.
At Harvard, Katz and then professor Felix Frankfurter edited a casebook on federal jurisdiction and procedure.
[3] According to former attorney general Edward H. Levi, Frankfurter brought Katz to the attention of the president of the University of Chicago at the time, Robert Maynard Hutchins.
He was recruited by the law school in an attempt to foster the interdisciplinary approach to legal education for which Chicago had been renowned.
[1] Paul G. Kauper, a professor at the University of Michigan Law School, observed the following about Katz's scholarship in this area: In his writings on the subject he has revealed insights and developed a canon of constitutional interpretation which have earned him a position of preeminent mentor ... A rich scholarship, penetrating analysis and insights, and mature reflection coupled with grace in writing, sensitivity to underlying values, a sense of intellectual integrity, respect for the views of others, and a kindly humor have all contributed to the effectiveness with which he has presented his views.