The disruptive innovation framework has been suggested to enhance new venture sustainability in resource-constrained contexts. This paper explores the role of human capital and strategic posture on disruptive innovation capability in low-income and resource-constrained environments. Using a generic qualitative inquiry strategy, we develop propositions tested by 20 in-depth interviews with entrepreneurs and industry role players in the South African startup incubation sector. Data from the interviews were analyzed through thematic analysis with constant comparison. The findings suggest that adopting an emerging market orientation and taking strategic risks assists in identifying the right consumer target market. Innovativeness is linked to effective product development processes, and a learning orientation contributes to the development of the skills and capabilities required for successful innovation in resource-constrained environments. Additionally, the findings emphasize prior founder knowledge and industry experience in shaping the strategic posture of entrepreneurs. Resource-constrained contexts vary significantly across regions. Our study contributes to the body of knowledge on disruptive innovations and small business sustainability in resource-constrained environments by investigating entrepreneurial dynamics in South Africa.