This article aims to contribute to women’s business history by linking research on corporate networks with research on female directors. To do so, we investigate the effect of the Swiss corporate network on the entry of women into boardrooms, and the effect of board feminisation on the Swiss corporate network and elites. We draw on a large database of Swiss elites, which includes board members and chief executive officers (CEOs) of the 110 largest Swiss firms from the beginning of the twentieth century to the present. The results show that during the twentieth century, a dense corporate network and a strong class cohesion within the male economic elites made it very difficult for women to gain access to these boards. A few female directors were first found in family firms, then in cooperatives within the wholesale and retail trade sector. They did not accumulate positions of power like men and remained ‘second-class’ elites. At the end of the twentieth century, equality was perceived as potentially profitable for firms. This led to an increase in the presence of female directors in all firms, the diversification of their profiles, and the emergence of a female ‘inner circle’. The assertion of board diversity must, however, be tempered by recognising the enduring geographical and social backgrounds of a large proportion of the directors.