The functional approach of the Technological Innovation System (TIS) has become important in innovation theory to understand the dynamics of technological innovations. Until now, TIS has mainly been applied top-down from a policy perspective. The aim of this study was to investigate whether TIS can be used in the management domain, from an actor-oriented perspective, to explain the dynamics in which technological start-ups are involved when developing innovations. We interviewed the founders of 24 technological start-ups about their experiences with the developmental processes of their innovations. Our results highlight that the functions of TIS provide a useful framework to structure the interactions of technological start-ups. Especially the functions ‘Resource Mobilisation’ and ‘Legitimation’ appeared to be important functions for start-ups when developing an innovation. Our findings show that TIS is a promising framework for the strategic management domain that can offer guidance in the development of innovations.