Leo is a Pediatric Dermatologist and Assistant Professor at the Washington University in Saint Louis School of Medicine in the Department of Medicine, Division of Dermatology, with secondary appointments in the Department of Radiology, and the Department of Pediatrics. He joined the faculty in 2021.

After studying Chemical Engineering at Cornell University, Leo completed his MD/PhD training at Washington University School of Medicine, earning his doctorate in physics in the laboratory of Sándor Kovács, MD, PhD. He then completed a fellowship in pediatric dermatology at the School of Medicine and a residency in dermatology at Barnes-Jewish Hospital before joining the laboratory of Samuel I. Achilefu, PhD, as a postdoctoral researcher.