Ruslan Medzhitov obtained his PhD from Moscow State University in 1993 and performed his postdoctoral studies with the late Charles A. Janeway Jr. at Yale University School of Medicine. In 1999, he joined the faculty of the Department of Immunobiology and is currently a Sterling Professor of Immunobiology at Yale University School of Medicine, and an Investigator of the Howard Hughes Medical Institute.

Medzhitov discovered mammalian Toll-like receptors and characterized their role in the immune system. He helped to define the mechanisms of TLR-mediated signaling, gene induction, and inflammatory responses in physiological and pathological conditions. His studies demonstrated the requirement for innate immune recognition for the induction of adaptive immune responses.

His awards include the Searle Scholarship, the William B. Coley Award from the Cancer Research Institute, the Emil von Behring Award, the AAI–BD Biosciences Investigator Award, Doctor Honoris Causae from Munich University and Utrecht University, the Blavatnik Award for Young Scientists, the Howard Taylor Ricketts Award, the Lewis S. Rosenstiel Award, the Shaw Prize in Life Science and Medicine, the Vilcek Prize in Life Sciences, the Else Kröner-Fresenius-Foundation inaugural international prize in immunology, and the inaugural Lurie Prize in the Biomedical Sciences. He is a member of the National Academy of Sciences, USA, a member of the National Academy of Medicine, a fellow of the American Academy of Microbiology and a foreign member of the Russian Academy of Sciences.