The continuous transformation of the labor market, characterized by great instability and uncertainty, and by rapid technological changes, has strongly influenced the construction and management of career paths. Nowadays, individuals are faced with careers that are fluid and boundaryless, characterized by discontinuity and a variety of organizations to deal with. In this scenario, the ability to adapt and react to continuous changes in the labor market and in organizations is now a priority for workers. This study presents the psychometric properties of the construct of Career Ability measured through Proactive Personality and Boundaryless Mindset as proxy variables in a sample of 579 adults enrolled at the University of Cagliari (Italy), or recently graduated therein. We aim to rate the factorial structure of the items and to evaluate their multi-group invariance regarding the gender variable. Moreover, the criterion and concurrent validity were assessed. The instrument shows good psychometric characteristics; factorial structure, factorial invariance in relation to the gender variable, concurrent, and criterion validities were confirmed.