Background. Positive healthy organizations perspective aims to promote the virtuous circle of employee wellbeing and success of organizations. In this framework, human capital sustainability leadership has been advanced as a higher-order construct comprising four leadership styles: ethical, sustainable, mindful, and servant. Positive healthy organizations perspective also supports the value of positive psychological resources and strengths of workers in a prevention perspective, included a primary preventive approach. Emotional intelligence (EI) has been recognized as a positive primary prevention resource since it is trainable in contrast to personality traits which are recognized stable in the literature.

Aims. The present study aims to investigate the contribution of trait EI in mediating the relationship between personality traits and human capital sustainability leadership.

Method. The Big five questionnaire (BFQ), the Trait Emotional Intelligence Questionnaire Short Form (TEIQue-SF), and the Human Capital Sustainability Leadership Scale (HCSLS) were administered to 381 Italian Workers. A series of five mediation analyses using the bootstrap method was performed.

Results. Results showed a statistically significant mediating role of trait emotional intelligence in the relationship between all the Big Five personality traits and human capital sustainability leadership with a mediator effect size ranging from R²= 0.22 (p < 0.001; BFQ Emotional stability) to R²= 0.35 (p < 0.001; BFQ Openness to experience).

Conclusion. Being emotional intelligence increasable via training, these results suggest that emotional intelligence could be a valuable area for research and intervention to promote human capital sustainability leadership style, as well as other psychological resources for positive healthy organizations.