High rates of principal turnover nationally mean that school districts constantly are called on to recruit and select new principals. The importance of a school's principal makes choosing candidates who will be effective paramount, yet we have little evidence linking information known to school districts at time of selection to principal's future job performance. Using data from Tennessee, we test the degree to which observable information about novice principals from prior to entry, including qualifications, work history information, and effectiveness in prior roles, predicts practice ratings assigned to them in their initial years in the principalship. We find that educational attainment and years of experience in other jobs hold little predictive power. Performance ratings received as an assistant principal (AP) or teacher, however, do predict principal effectiveness. Moreover, APs who previously worked in schools with highly rated principals are more likely to be effective upon transitioning into the principalship.