Purpose: This study aims at investigating the indirect effect of soft skills on career engagement through the role of psychological capital (PsyCap) in different age groups. The social cognitive theory (SCT) and job demands-resource model (JD-R) were employed to explain the effect of perceived skill mastery on PsyCap and career engagement. Design/methodology/approach: The data were collected from 707 high school students, 150 university students and 165 employees using a three-wave data collection technique. This study measured soft skills, PsyCap and career engagement at different age groups (i.e. high school students, university students and employees). The data were analysed using a moderated-mediation technique. Findings: The results showed that soft skills positively influenced PsyCap and eventually increased career engagement in all age groups. However, the effect was stronger for students (both in high school and university) than employees in the workplaces. Unlike most students, employees related soft skills to performance. Regardless of the effect on performance, students would be more likely than employees to perceive soft skill mastery as a source of efficacy. Research limitations/implications: First, the education system should direct more attention to developing students' non-cognitive skills. Second, people should understand that their career advancement continues in the workplace context. Organizations can foster employees' soft skills by providing more opportunities to develop new skills. Originality/value: This study sheds light on the importance of soft skills beyond academic and workplace performance. This study is among the few empirical investigations that reveal career engagement factors across different career development stages.