Leslie J. Klaff was born in the coastal city of Durban, South Africa and received his medical education at the University of Witwatersrand, Johannesburg, South Africa. After 2 years of medical residency in Johannesburg he spent a year in London, UK furthering his education and then returned to Cape Town, South Africa where he completed his residency. He then joined the Endocrine Unit at the University of Cape Town, where he developed his life-long interest in diabetes and its complications. He completed a PhD and a clinical fellowship in Endocrinology and joined the full-time faculty at the University of Cape Town in 1981. In 1983 he was recruited to the University of Washington, Seattle, as a sub-investigator in the multi-centered international Diabetes Control and Complications Trial. He rose to be an Associate Professor of Medicine at the University of Washington, but in 1989 left to enter Endocrine practice in Renton, WA. In 2006, Dr Klaff retired from practice to concentrate on his research.
Dr Klaff is currently an Emeritus Clinical Professor of Medicine at the University of Washington. He is board certified in Internal medicine and Endocrinology and is a Fellow of the Royal College of Physicians (Edinburgh, UK) and a Fellow of the American College of Endocrinologists. He is an author on over 50 scientific articles and book chapters. Dr. Klaff is married to Denise and has two married children and 5 grandchildren.