Deetz was appointed Assistant Director at Plimoth Plantation in 1959, and implemented changes to the way the heritage site was run. He removed everything which would not have been in the settlement in 1637, such as interpretative signs, and introduced first-person interpretation by costumed staff: "part of a simulation of life in which all senses are involved, feeling, thinking, and acting in an environment as close to reality as research could make it". Deetz and his wife, Patricia Scott Deetz, brought up their nine children whilst he was working at the site. Deetz worked at Plimoth Plantation until 1978, when he took up a position at University of California, Berkeley.