Carpenter’s earliest fieldwork was centered on Haudenosaunee sites in upstate New York and various locations in Pennsylvania. He began his studies in anthropology in 1940 at University of Pennsylvania, under Frank G. Speck, a mentor whom he would count as a profound influence for the rest of his life. During the years 1940-41, as part of a Works Progress Administration archaeology project, Carpenter co-led with Wesley Bliss the field excavations of the three Sugar Run mounds, a Middle Woodlands site in the Allegheny River valley, western Pennsylvania, utilizing a crew of Seneca members of the Allegheny reservation. After the interruption of World War II, during which he served in the South Pacific as a Marine captain, Carpenter resumed graduate study, earning his Ph.D. in 1950. That same year, he published the findings from his earlier Sugar Run field report with the American Philosophical Society, as “The Ancient Mounds of Pennsylvania.”