Hartley spent a year at the University of Chicago, and another at MIT before being appointed as a lecturer at the newly established University of Warwick in 1966, and was promoted to reader in 1973.
Hartley held academic positions at the University of Chicago for one year and at MIT for another year before being appointed as an educator at the newly formed University of Warwick in 1966, and was subsequently elevated to a more prominent role as a reader in 1973.