As expatriation and cross-border assignments have become increasingly frequent, so has the need for research on what makes a successful expatriate. The objective of this study is to further understand the working expatriate’s acculturation process, which is the process of learning and acquiring the requisite skills to successfully inhabit a new cultural realm. We used a mixed-methods approach, quantitatively measuring work locus of control, acculturation strategies and sociocultural adaptation, and investigating the expatriate’s subjective experience phenomenographically. We interpreted these results using culturalhistorical activity theory. We found that work locus of control and choice of acculturation strategy affect the acculturation process, suggesting that an assimilator with an internal work locus of control adapts easiest. The qualitative differences were more nuanced, showing that expatriates view acculturation in terms of four separate but intertwined relationships; to work, to culture, to social relationships, and to their self-identity. This study contributes to expanded knowledge on the acculturation process in general, but particularly on the role that work plays in expatriate acculturation. Finally we make suggestions for application of these findings and future research.