Given the importance of entrepreneurial thinking and acting as a meta-skill in the future world of work, we focus on the emerging entrepreneurial mindset in the transition to adulthood. We study the role of personality characteristics and age-appropriate entrepreneurial competencies (leadership, self-esteem, creativity, proactivity motivation) in the prediction of entrepreneurial alertness and career intention. Using two-wave longitudinal data from high schools in Helsinki, Finland (N = 523), we tested a mediation model with competencies as mediators between personality and entrepreneurial alertness and intention. The findings suggest that entrepreneurial alertness and career intention a) are rather independent career development constructs of the emerging entrepreneurial mindset, b) are both an expression of an entrepreneurial personality structure, and c) are predicted by different, underlying competencies: leadership and self-esteem mediated the personality—entrepreneurial intention link, and leadership, creativity, and proactivity motivation the personality—entrepreneurial alertness link. Consistent with the balanced skill approach to entrepreneurship, the intradindividual variety of these competencies was also a valid mediator, but did not show incremental predictive power. Implications for research and practice are discussed.