The present study aims to explore student-teachers' (STs') progress in understanding social urban sustainability and how it is affected through the development of digital stories and engagement in civic actions. Participants were 44 STs enrolled in a Department of Primary Education located in Northern Greece. Although participants were aware of the principles of sustainable development and education for sustainability, none of them had familiarity with social or urban sustainability. Three individual digital concept maps constructed before, intermediate and after the end of the course served as data sources. Both quantitative (significance testing, effect sizes, and confidence intervals) and qualitative (categories development) methods of analysis were implemented. Results indicate a sound improvement of STs' understanding even in the intermediate concept maps with the most significant proposition gains associated with the society pillar. Moreover, despite the significant improvement in understanding of all main pillars of sustainability, this improvement was unbalanced because a minority of subcategories constituted the majority of STs' propositions in all settings, indicating a strong and constructive combination between theory and praxis for the advancement of STs' learning.