The purpose of the current study is to examine the mediating processes through which human capital (e.g. education and work experience) contribute to objective indicators of career success (e.g. salaries and promotions). We are particularly interested in the ways in which cognitive ability and conscientiousness help explain the process through which human capital gets translated into performance effectiveness and tangible career attainments. Results from meta-analytical structural equation modelling show that individuals' cognitive ability and conscientiousness mediate the effects of both education and organizational tenure on in-role and extra-role job performance. Ultimately, both in-role and extra-role job performance positively influence employees' salaries and promotions. The article concludes with implications for theory development and management practice.