Dr. Markinson graduated from the New York College of Podiatric Medicine in 1981. After completing surgical residency and fellowship, he was appointed to the facult, achieving the rank of Professor in the Division of Medical Sciences. He opened a private practice in Brooklyn, New York in 1985. Dr. Markinson then served as a Fellow from September 199 to June 1995 in the department of Dermatopathology at the University of Medicine and Dentistry in New Jersey. Shortly thereafter, Dr. Markinson founded the Podiatric Pathology service at the Mount Sinai School of Medicine.
In 1998, he joined the full-time faculty of the Mount Sinai School of Medicine, where he is an instructor in the Department of Dermatologic Surgery. In 2004, he was elected to the Board of Trustees of the Council for Nail Disorders, and is a consultant to Bako Podiatric Pathology Laboratories, and several pharmaceutical companies in the dermatology space.