This paper presents a study of university social responsibility (USR), carried out through an innovative educational action. The students of the studied classrooms in the University of the Basque Country (UPV/EHU) collaborated with a social entity Emmaus Social Foundation dedicated to environmental sustainability, social justice and the social and solidarity economy to provide community services through a service-learning methodology. Using a mixed method approach, we combined the practical experience of the social entity with an active student-centred teaching methodology in order to foster the acquisition of general and specific competencies related to sustainability and social justice. The aim was to create learning connections between members of the university community and links with the environmental and social reality of the Basque Country. This pilot study was carried out in the first term of the 2018-2019 academic year. This work allowed (a) critical knowledge to be generated by incorporating and hybridising discussion elements of social justice, such as sustainability; (b) intergenerational participation processes to be generated between elders, university students and social organisations in order to acquire general and specific learning competencies and (c) social and environmental needs to be addressed through community services.