Earlier studies have investigated the impact of managerial/entrepreneurial characteristics on general strategic issues in the context of small and medium-sized companies. However, the manager/entrepreneur’s mindset in designing and implementing sustainable business strategies in the context of social enterprises has not been addressed. In particular, the link between characteristics of the manager/entrepreneur at the individual level and the implementation of business sustainability dimensions at the firm level remains under-researched. We advance theory into this area by theorising how personal characteristics might influence the social enterprise manager readiness for the long-term sustainable business through mediating construct such as mindset. We find that if an entrepreneur has a pragmatic mindset, the readiness of the social enterprise for the long-term sustainability strategy will be higher.