Globalisation and its related social, economic and political challenges is making the South African business environment ever more competitive, with firms finding that agility, flexibility and continuous self-renewal are essential to maintain their positions. To exploit their current competitive advantages and explore future opportunities, firms are increasingly adopting corporate entrepreneurship (CE) – a type of proactive behaviour.The aim of this research was to determine the extent to which South African firms in the financial, retail and telecommunications sectors use CE methods, and to uncover the most important internal organisational factors that influence their use. A literature review of all the themes relating to the topic was done, from which five propositions were developed and a questionnaire was compiled. After four suitable companies had been identified (with the aid of five CE experts), the questionnaire was used in 24 interviews conducted across these four case study organisations. The results were analysed and used to draw conclusions relating to the aim of the research.From the research findings, the author has been able to construct a model that managers of South African companies operating in the fields of finance, retail and telecommunications could use to improve their companies’ financial performance.