This qualitative study based on 34 semi-structured interviews with ATCKs explored the effects of early life international exposure on career capital. The results show that a globally mobile childhood has extensive long-term impacts on ATCKs' career capital in the areas of knowing-why (motivation and identity), knowing-how (skills and competencies), and knowing-whom (relationships and networks). Alongside positive impacts, several negative career impacts were also found — contradicting purely positive framings of the ATCK career advantage. Published in the Journal of Global Mobility.