Successful post-acquisition integration hinges on combining hard and soft integration, but insights into how this can be done are scarce. We develop a dynamic model of post-acquisition integration through an in-depth inductive study of a cross-border acquisition. Our model illustrates that the combination of hard and soft integration decisions sets in motion intergroup interaction processes that influence both the realization of synergies and collaborative intentions. Our study advances the M&A literature by elucidating how hard and soft integration dynamically interact in their effects on post-acquisition integration outcomes. In doing so, we respond to the call for more research on the temporal nature of integration processes. Finally, we reveal that a singular or monolithic approach to post-acquisition integration is unlikely given that different units are likely to have different integration needs depending on their degrees of interdependence and autonomy.