Despite decades of efforts to promote social mobility, studying for higher education maintains or even exacerbates social inequalities. Interventions, including employability classes and careers advice and guidance, have not succeeded in 'levelling the playing field' for students. To understand why inequalities persist despite these efforts, it is important to understand how students from different backgrounds acquire and apply various forms of capital. The graduate capital model is used in this article to explore how five dimensions of capital (human, social, cultural, identity and psychological dimensions) interact, drawing on data from interviews with high and low socio-economic status (SES) university students. While in general lower-SES students found employability classes helpful in equipping them with the human capital required in order to succeed on today's graduate labour market, in contrast to their high-SES peers they struggled to understand the importance of and mobilise this and other forms of capital promoted in those classes. The crucial forms of capital that seem to interact with all other capitals are social and psychological. Universities therefore need to find a way to help low-SES students build and apply these forms of capital and alleviate barriers to their mobilisation.