The ethnographic encounter between the earliest generation of professional American anthropologists and the Indigenous peoples of the Philippines in the early twentieth century produced not only knowledge about these peoples and their cultures, but it likewise produced the anthropologist. This dissertation examines the works and lives of Albert Jenks, Frederick Starr, William Jones, and Laura Benedict to analyze how the category of the anthropologist in the field was gendered through their encounters with their Philippine interlocutors. What emerges here is a history of masculinity and anthropological fieldwork, framed against the inescapable context of American colonial rule in the Philippines. This historical anthropology is undergirded by an analysis of three axiomatic ideas in the history and anthropology of sex and gender in Southeast Asia: the “high” status of women; the malleable image of the man of prowess; and the concept and practice of gender pluralism and its transgression. The dissertation rethinks these axioms, not only to argue for their continued salience within Southeast Asian area studies, but also to demonstrate their utility as categories of analysis for the history of anthropology.