Social class of origin is apparently an imperceptible attribute among doctorate holders seeking academic jobs. Yet, recent studies in different countries reveal that social class of origin may still be influencing the chances of PhD holders from low social class being hired at prestigious universities. Drawing from the theory of social and cultural reproduction, normative 'fair' academic hirings frameworks, and qualitative evidence collected in Chile, this research identifies the mechanisms that trigger (un)conscious social class bias in the stages of recruitment and selection of candidates in seven academic departments in economics and industrial engineering (46 interviews). Findings did not prove explicit classism manifestations, but practices of inclusion/exclusion of candidates based on the prestige of PhD-granting universities, and networks. These reproduce the relationship between social class and unequal chances of being connected to prestigious universities. Recommendations to address (un)conscious social class bias in academic hiring are discussed.