 After working as assistant to the Sheriff of Cook County Jail, he became the Senior Research Sociologist and Trustee at the Kinsey Institute for Research in Sex, Gender, and Reproduction at Indiana University in Bloomington, Indiana from 1959 to 1968.At the Kinsey Institute, Gagnon worked with his friend from his graduate student days at the University of Chicago, William Simon, and they started a short but highly productive collaboration.Their key work, "Sexual Conduct" (1973), was developed during this period.