To cope with the challenges of 21st-century careers, the research on psychology of sustainability and sustainable development complements the psychology of work perspective with an emphasis on factors that foster the workers' well-being, decent work, and decent lives in healthy organizations. In this framework, individual eudaimonic well-being (EWB) is among the most relevant factors that may enhance decent and sustainable life projects and careers. Human capital sustainability leadership (HCSL) constitutes a resource for positive relatedness in organizations being linked to EWB. Innovative behaviors (IBs) are crucial for the sustainable development of organizations. This study investigated the relationships between IBs and EWB, testing the mediating role of HCSL in 353 Italian workers, controlling for participants' age and gender. HCSL fully mediated these relationships and emerged as a promising resource in linking IBs and EWB, supporting workers to achieve sustainable careers, decent work, and decent and healthy lives.