John L. Ziegler, M.D., M.Sc. was educated at Hotchkiss School and Amherst College where he received a degree in English Literature in 1960. After receiving an M.D. at Cornell University Medical College he undertook residency training at Bellevue Hospital and Memorial-Sloan-Kettering Hospitals in New York City. Joining the National Cancer Institute in 1966, he embarked on a long career in cancer research. He was the founding Director of the Uganda Cancer Institute in 1967 and was honored by the Lasker Award in 1972 for his research on the cure of Burkitt's lymphoma. During the 1970s he was Chief of Pediatric Oncology and later Director of Clinical Oncology at the National Cancer Institute.
In 1981 he moved to the University of California San Francisco as professor of medicine in residence, and Chief of Staff for Education at the VA Hospital. Here, he participated in the early research on the AIDS epidemic, being the first to show an association with malignant lymphoma. Ziegler became the Director of the UCSF AIDS Clinical Research Center and made many scientific contributions in the area of HIV-associated malignancies, both in the USA and in Uganda. In 1997 he earned a masters degree in epidemiology at the University of London. Over the past ten years, Ziegler has directed the UCSF Cancer Risk Program at the Comprehensive Cancer Center, now one of the leading genetic counseling and testing centers for hereditary cancer in northern California. Ziegler has authored over 260 scientific articles, chapters and reviews and is the recipient of numerous awards that honor his work in cancer and global health.
Ziegler has had a career-long interest in medical education and has taught clinical medicine for eight years at Makerere University in Kampala, Uganda. He has also taught at Cambridge University and at the London School of Hygiene and Tropical Medicine as a Visiting Professor.