[3] There he began his research career, working in the laboratories of organic chemist Josef Fried, biochemist Kan Agarwal, and bacteriologist Malcolm Casadaban.

[2][4] In 1984, he began a dual MD–PhD program at Cornell Medical College and Rockefeller University, working on DNA repair in bacteria with Peter Model and Norton Zinder.

Pioneering research with the model budding yeast Saccharomyces cerevisiae discovered TOR and FKBP12 as the targets of the immunosuppressive and antiproliferative drug rapamycin, now widely used in organ transplantation and cancer chemotherapy.

;[49] Sex in Fungi: Molecular Determination and Evolutionary Implications, ASM Press 2007, editors: Joseph Heitman, James W. Kronstad, John W. Taylor, and Lorna A.

;[50] Cryptococcus: From Human Pathogen to Model Yeast, ASM Press 2011, editors: Joseph Heitman, Thomas R. Kozel, Kyung J. Kwon-Chung, John R. Perfect, and Arturo Casadevall.

;[51] Molecular Principles of Fungal Pathogenesis, ASM Press 2006, editors: Joseph Heitman, Scott G. Filler, John E. Edwards Jr., and Aaron P.

;[52] Human Fungal Pathogens, Cold Spring Harbor Laboratory Press, 2015, editors: Arturo Casadevall, Aaron P. Mitchell, Judith Berman, Kyung J. Kwon-Chung, John R. Perfect, and Joseph Heitman.