The Young Masters Programme provides young people around the world with a net–based global–local learning environment for sustainable develop-ment. The present study investigates certain aspects of the implementation of this programme in the secondary schools of a Swedish municipality, in the context of the Lund Calling project. The research focuses on critical abilities to act globally, referred to as “knowledge capabilities”, and how they relate to the implementation process of initiating global learning for sustainable development (GLSD). A phenomenographic approach and semi–structured interviews were used in the investigation of the experiences of secondary school pupils, teachers and headmasters who participated in the project. Participants’ experiences of the changes carried out are described in relation to examples of knowledge capabilities needed for GLSD. Critical knowledge capabilities found to have been developed through the implementation were: to take command, and to collaborate. Critical knowledge capabilities perceived as necessary, but not developed through the programme were: to be prepared, to act in a transdisciplinary manner, and to lead for a holistic understanding