The purpose of this article is to deepen our understanding of twentieth-century masculinity by considering the social function of facial hair. The management of facial hair has always been a medium of gendered body language, and as such has elicited a nearly continuous private and public conversation about manliness. Careful attention to this conversation, and to trends in facial hairstyles, illuminates a distinct and consistent pattern of thought about masculinity in early twentieth-century America. The preeminent form of facial hair—mustaches—was used to distinguish between two elemental masculine types: sociable and autonomous. A man was neither wholly one nor the other, but the presence and size of a mustache–or its absence—served to move a man one way or another along the continuum that stretched from one extreme to the other. According to the twentieth-century gender code, a clean-shaven man’s virtue was his commitment to his male peers and to local, national or corporate institutions. The mustached man, by contrast, was much more his own man: a patriarch, authority figure or free agent who was able to play by his own rules. Men and women alike read these signals in their evaluation of men.