To facilitate organizational change and improve corporate sustainability, this study identifies change agents and factors driving sustainability integration in the core business of companies. The survey on corporate sustainability management in Africa, with focus on smaller large-sized companies (revenue of #50-300 million, at least 250 employees), fills the research gap between studies commonly concentrating on the largest companies and on SMEs. Companies mainly established integrated cross-departmental sustainability management teams, which required change in the routines of employees and change agents to drive the projects. Possible locations of these change agents were identified.The earliest theme to be explored, is the story of how and why some conventional industries sought to become less polluting. Researchers have dated this phenomenon back to the late 19th century, showed it gained momentum from the 1960s, and explored how it resulted in the mainstreaming of sustainability rhetoric, and sometimes practice, in large Western corporations from the 1980s.