This article unearths the salient factors that trap the aspiring middle class in their progression towards a stable middle class in the City of Johannesburg, South Africa. The study utilises a quantitative case study design, drawing on a sample of 449 aspirants and 578 middle-class heads of households from the 2021 Gauteng City-Region Observatory Quality of Life Survey. A binary logistic regression model was used to analyse these salient factors (key determinants) and their impact on the social mobility of the aspirant middle class. Findings reveal a significant relationship between social mobility and education, racial inequality, asset ownership, access to economic opportunities and proximity to amenities. We suggest local government policies that positively influence the conditions of these determinants for sustained mobility of the aspirant middle class over time.