While most research on family business longevity focuses on how internal corporate governance issue impact resilience, the aim of this article is to foreground the relevance of external environmental factors, and to do so in an internationally comparative perspective. By historically comparing the largest family businesses in Germany and Spain in the twentieth century, we find that they differ significantly in age and ask how external factors help us better understand these variances. After analysing the institutional framework of the two countries during the second part of the 20th century, we explore the strategic responses developed in reaction to that framework by four of the largest family businesses in the two countries. With this, we strive to capture the interdependent nature of internal decision-making processes and external environmental changes, ultimately arguing for a more holistic understanding of family business resilience over time.