This paper investigates the direct and indirect ties between various leadership styles, namely, instructional, transformational, transactional, and laissez-faire leadership, and the instructional practices of teachers by applying a structural equation model. For this purpose, we analyzed survey data of n = 3,746 teachers from 126 schools collected by the Hamburg school inspection in Germany between 2012 and 2015. The underlying model is based on Leithwood’s framework for guiding research on leader effects on learning and instruction. First, the results show that a bi-factor model seems to be the best measurement model. Next, it is shown that mediating variables are influenced by a leadership core as well as by different leadership facets. Third, we found that for influencing complex instructional practices like cognitive activation with challenging content, a combination of leadership styles is most promising, while for classroom management instructional leadership is the only and, thus, the primary determinant.