Katz worked as an assistant member of the Department of Virology and Molecular Biology at St. Jude's Children's Research Hospital in Memphis, Tennessee and had a concurrent appointment as an assistant professor at the University of Tennessee, Memphis, from 1990 to 1992.[3] Katz joined the Centers for Disease Control and Prevention (CDC) in 1992 as chief of the Immunology and Viral Pathogenesis Section in the Influenza Branch within the Division of Viral and Rickettsial Diseases.[2]