Thomas Mann was a diligent reader, with pencil in hand, of popular science books. His works display not only a basic knowledge in biology, but also well-informed insights about microbiology, zoology, evolutionary biology and paleontology. In particular, Haeckelian themes and Leitmotive become evident in some major novels such as Der Zauberberg, Doktor Faustus or Bekenntnisse des Hochstaplers Felix Krull, so that there is a broad agreement on the significant role played by the biological discourse within his narrative fiction. Thus, this article attempts to throw light on the evolutionary features of Mann’s considerations about the aesthetic individual. In this regard, after recalling the main features of Mann’s conception of life as bios, the article considers first the idea of evolution developed from his early writings to the later ones. Second, it discusses the most important single elements of this idea, namely mimicry, natural selection and aesthetic evolution, intending it as a progression towards beauty, variety and organic completeness. Finally, the article focuses thematically on Mann’s reflections on the aesthetic individual, referring to the concept of Homo aestheticus, which stems from the contemporary evolutionary theory.