In recent years, citizen-led initiatives have emerged to complement top-down development policies, particularly to pursue sustainability objectives and benefit traditionally left-behind communities and places. Existing research on this phenomenon in Italian mountain areas suggests a primary emphasis on revitalizing the natural environment, preserving local culture and traditions, and delivering social services to address the absence of public facilities. However, there is still a lack of understanding regarding their profiles, key features, social and environmental impacts, and challenges at the national level. As part of a broader research project, this empirical work contributes to the literature on bottom-up sustainability-oriented initiatives in mountain regions by conducting an explorative interregional online survey. We gathered original data on 196 initiatives from the mountain areas of the Italian regions of Basilicata, Lombardia, Marche, Sicilia, and Veneto. The findings indicate that our sample shares common traits, visions, and values, making a positive contribution to the sustainable development of their respective territories. However, these initiatives must contend with internal and external challenges to enhance their resilience and impact. Importantly, the research may support policymakers at various levels in the design of public policies that harness the full potential of bottom-up initiatives, ultimately enhancing the development and sustainability of these lands.