Little is currently known about how the realisation of operating synergies and dissemination of available knowhow in the merged firm are managed in post-merger phase. We provide insights on the process of integrating operating synergies by focusing on the critical success factors facilitating integration of the skills of the merged banks. We draw on three perspectives and reconcile them with three dimensions of integration. In-depth interviews were conducted with Nordea bank´s managers from four Nordic countries. Review of extant literatures shows that most mergers fail during the integration process. Having learned from the mistakes of previous mergers, Nordea´s “leading star” for managing its post-merger integration process were expressed as Focus, Speed and Performance from top management. Therefore, a hands-on leadership styles, vision-led thinking, a bias for action, involvement of the entire staff, continuous focus on customers, open and honest communication with employees are critical to success. We conclude that the motive for a merger  have an important impact on the degree of interaction and degree of integration; This study deepens previous findings by, among others, synthesising three theoretical lenses into an integrative model and addresses post-merger issues with a sharp eye towards clear managerial relevance.