In 1957 he began working on the River Basin Survey site in Missouri. This work inspired him to get his Ph.D dissertation in "An Archaeological Approach to Kinship Change in Eighteenth Century Arikara Culture." Deetz then became an Assistant Professor of Anthropology at the University of California. He also taught at University of California, Santa Barbara, Harvard, Brown, William and Mary, the University of Cape Town, the University of California, Berkeley, and the University of Virginia. While teaching at the University of California, Deetz teamed up with J. O. Brew and Harry Hornblower to excavate sites related to North American colonial archaeology. He would later meet Henry Glassie who was his inspiration to write "In Small Things Forgotten: The Archaeology of Early American Life", which was published in 1977.