This article examines the significance of Caroline Bond Day's vindicationist anthropological work on mixed‐race families early in the 20th century. Day used the techniques of physical anthropology to demonstrate that mixed‐race African Americans were in no way inherently deformed or inferior. Using Day's published work and unpublished correspondence, I show that her study was noteworthy for two reasons. First, unlike most other anthropologists of her time, but presaging later scholars, she studied her own family and social world, a perspective that both gave her unique data unavailable to others and removed barriers between herself and her subjects. Second, as a mixed‐race African American woman, she found herself not only fighting preconceptions about the racial inferiority of African Americans but also serving as a liaison between her research subjects and mainstream, White‐dominated physical anthropology. This article argues that Day's importance as a scholar lies not only in her argument against racial inferiority but also in the outsider‐within status that allowed her to make her case within academic anthropology in the early 20th century.