Gender equality is one of the Sustainable Development Goals. Management is one of the jobs that more clearly needs a gender perspective. Women leaders have found a way around the labyrinth to get to the top, which might have developed their personal resources such as psychological capital. Women leaders experience an inter-role conflict when work and family demands are mutually incompatible, affecting negatively their well-being. This study aims to analyze the mediation role that work–family and family–work conflict plays between psychological capital and well-being (engagement and burnout) when moderated by the number of children. In total, 202 Spanish women leaders participated in the study. Results of the mediated moderation model using Model 14 of the macro PROCESS for SPSS software show that psychological capital buffers the negative effects that experiencing work–family conflict has on well-being when having children. The well-being of women leaders is not affected when dealing with family interfering work conflict and having children. As such, women leaders who have children rely on their psychological capital to successfully manage the family demands affecting their work and to reduce the negative effect of work–family conflict on their well-being. Theoretical and practical implications are discussed from the psychology of a sustainability perspective.