As a field of study and practice, strategic human resource management (SHRM) has come a long way in recent years. Still, at this point, the domain incorporating and connecting human resource strategy (HRS) and organizational effectiveness (OE) is essentially a theoretical and empirical "black box". Here we use our ongoing research on people in agile organizations to peer into this "black box" and draw implications for future theorizing and research. Suggestions are made for reconceptualizing OE, incorporating organizational capability as a key concept, taking a broader than usual view of HRS, and systematically assessing vertical and horizontal alignment of HR activities.