In business thinking, ‘core competencies’ have long been seen as the critical factor that distinguishes great from good. Great companies have strong core competencies that they constantly leverage and develop. On the other hand, companies who do not understand their own strengths and weaknesses cannot execute at the highest proficiency. Their growth initiatives fail, not because they lack commercial potential, but because they fail to apply the same due diligence to their competencies they so naturally apply to their finances. Understanding competencies entails understanding culture, and few companies know how to approach this topic beyond the gut feel analyses of executives or the rare employee survey. In this paper, we use a large-scale study for the medico company Coloplast as a case for how to use ethnography to rigorously study competencies and leverage growth. We show how understanding the effects of culture and competence on market performance led to significant changes in Coloplast’s strategy and make the case that core competence can and should be studied through ethnography as an integral part of the corporate strategy process.