Supplementary and Complementary Congruence at the Apex of the Organization: Management and Board as a Strategic‐Oriented Multiteam System

Abstract Our knowledge of the top management team (TMT) and board interface in the context of major strategic decisions remains limited. Drawing upon the strategic leadership system perspective (SLSP) and the interface approach, we argue that the two groups constitute a strategic‐oriented multiteam system and consider how supplementary (similarity) and complementary (interacting variety) congruence of international and functional backgrounds influence strategic decision‐making. Looking at the internationalization decisions of the largest public firms in the UK, we find that complementary congruence of international backgrounds and supplementary congruence of functional experience promote the pursuit of new market entries. We extend the SLSP by showing how the cognitive TMT–board interface dynamics associated with supplementary and complementary congruence are important antecedents of strategic outcomes. Further, we find a boundary condition to the interface approach in strategic leadership research by identifying the underlying mechanisms that activate some TMT–board interfaces and not others.