Sustainable development (SD) is a multidimensional issue. However, research findings report a divide between students' awareness and behavior. It is identified that study programs are designed more for awareness outcomes, and not so much for behavioral outcomes. For higher-order learning outcomes manifested in a sustainable development behavior, the authors argue for a model based on an understanding of learning as boundary crossing. Based on this model, learning for sustainable development occurs in relating social practices, lifestyles, academic practices, professional practices, and students' digital practices. To inform teachers' approaches to teaching as an important driver of institutional change, we conducted a survey among students of urban and spatial planning in Slovenia. Examined factors included personal, academic, and digital predictors for sustainable development awareness, lifestyle, and behavioral intention. We hypothesized that a significant predictor for sustainable development behavior, which was measured as sustainable lifestyle and sustainable development behavioral intention, would be learning in social practices, and that learning in social practices would predict preferred teaching methods. The findings of hierarchical regression analysis indicated personal factors as the most important predictors of SD behavioral intention, and academic predictors as the most important factors for SD awareness. Digital practices were found to be the most important predictors of a sustainable lifestyle. Social practices of sustainable lifestyle, digital practices, and perceived teaching methods predicted students' preferred teaching methods. We discuss the future directions of sustainable development education, considering digital social media practices as essential boundary crossers.