During recent years, IT alignment research has gained considerable attention in both academia and practice. However, so far most studies focus on the strategic-to-strategic IT alignment dimension, thus omitting an integration of the strategic-to-tactical IT alignment dimension. By drawing upon assimilation and institutional theory, our research model depicts a perspective on IT project alignment that integrates both the internal strategic-to-tactical IT alignment and the external IT alignment dimension. The derived hypotheses were tested based on 189 responses from IT decision makers of U.S. financial services providers. The results from partial least squares analyses suggest the importance of internal as well as external IT alignment for IT project success. Moreover, the role of tactical middle management for the alignment to external dynamics seems to be underestimated in prior studies. Our results contribute to IT alignment theory by integrating a multi-level perspective emphasizing the complementary roles of strategic and tactical management levels.