Dr. Stuart Kornfeld is the David C. and Betty Farrell Distinguished Professor of Medicine at Washington University in St. Louis. He is best known for his work elucidating the processes governing lysosome biogenesis. His research continues to uncover roles for oligosaccharide biosynthesis, processing, and maturation in mediating proper folding and transport of proteins. In an interview with JCI Editor-at-Large Ushma Neill, Kornfeld discusses how his first biochemistry course, taught by Carl and Gerty Cori, and his work as a postdoctoral researcher in Luis Glaser’s lab led to his interest in the role of sugar moieties in cellular physiology. Kornfeld also discusses his early work with postdoctoral fellows Ira Tabas and Ajit Varki and graduate student Marc Reitman in characterizing the trafficking of lysosomal proteins. Finally, Kornfeld addresses the importance of mentors in the development of physician-scientists.