We examine top management team (TMT) structure and characteristics as potential endogenous antecedents of outside appointments of non-CEO senior executives, an executive category that has not yet received significant research attention despite its importance for corporate outcomes. In doing so, we draw on human capital and similarity-attraction theories, thus combining two complementary managerial decision rationales. Additionally addressing the pressing need for cross-country TMT research, this study empirically analyzes a unique sample of 880 non-CEO TMT appointments at large non-financial corporations in France, Germany and the UK between 2006 and 2010. Overall, the results show that TMT endogenous factors such as structure, new executive characteristics and incumbent TMT characteristics may hold significant explanatory power for new executives' origin. Beyond the individual explanatory factors, the comparative nature of the study reveals three distinct country profiles of the degree by which the two theoretical rationales appear to influence appointment decisions.