This article interrogates how Franz Schreker's Die Gezeichneten and its early reception reflected an uneasiness about the confines of manhood. As an opera with a complex genesis and a difficult reception history, Die Gezeichneten's allure comes from its resistance to being reduced to only one thing. I nevertheless seek to locate this opera around the time of its premiere towards the end of the First World War. I contend that Die Gezeichneten and its immediate reception charted a key transition in Austro-German masculinity. Specifically, the opera's early performances marked a move away from the period's normative models of bourgeois masculinity (and their corresponding ideas about appearance, health and nationhood) and towards an alternative masculinity preoccupied with degeneracy. I focus on the opera's masks, arguing that, through acts of concealment and disclosure, the opera's two male protagonists struggle to negotiate expectations of an emotionally controlled modern manhood, calling attention to wartime anxieties about what it meant to be a man. Such anxieties resulted in a hardening of attitudes towards the masculine gender, which influenced contemporary music criticism too. Die Gezeichneten's highly sensationalist early reviews relied on a language of degeneracy. Yet I suggest that the opera's initial reception captured a critical moment in this language's history before it was subsumed under Nazi ideology.