Dr. Seldin was born in New York City. He received his BA degree from New York University and his MD from Yale University School of Medicine. His residency in Internal Medicine was at New Haven Hospital. He was appointed to the faculty at Yale from 1944 to 1951 when he was recruited to the University of Texas Southwestern Medical School. He was appointed Chairman of Internal Medicine from 1952 to 1988, at which time he became Chairman Emeritus. He continues to be active in teaching and writing.
Dr. Seldin is widely revered as one of the greatest chairs of Internal Medicine in American medical history. He has trained literally thousands of medical students and residents, and many of his students occupy high academic positions. He is considered the intellectual father of The University of Texas Southwestern Medical School.