early U.S. ethnographer of American Indians, especially those of the southeastern United States. His investigations of the history, heraldry, and culture of the Cherokee and Kiowa included the deciphering of the Kiowa calendar and the discovery of an ancient ritual of the North Carolina Cherokee recorded in the native script. His most acclaimed work was The Siouan Tribes of the East (1894). His monograph, The Ghost-Dance Religion and the Sioux Outbreak of 1890 (1896), was the first full-scale study of a nativist religion arising out of a cultural crisis.

Mooney was largely self-taught. He had set out on an independent private expedition to Brazil when Maj. J.W. Powell, whom he stopped to ask for advice, persuaded him to take a position at the Smithsonian Institution's Bureau of American Ethnography. He remained with the bureau for the rest of his career.