Culturally congruent dietary patterns have evolved with geographic and societal traditions and can be traced as far back as pre-Hellenistic Greece. Today, the modern Mediterranean diet (MDiet) is recognized internationally as an anti-obesogenic cardioprotective dietary model consisting of plant-based foods native to the Mediterranean basin, fish, olive oil, and an active lifestyle. With the assumption that obesity and heart disease rates adversely affected life expectancy, the MDiet was identified by Dr Ancel Keys as a primary characteristic among people-groups largely immune to these trends. Following extensive research on how food quality affected human performance, Keys engineered the largest ecologic investigation of dietary habits and their effects on heart disease and longevity known as the Seven Countries Study. A new understanding of how regionally and culturally specific diets affected entire populations led to the introduction of the MDiet to the global public health community. This historiographic portrait of Dr Keys describes his humble beginnings, highlights critical points in his career, discusses his seminal research into diet and culture as protective agents, and details his legacy as the pioneer of the modern MDiet.