Textile industries are in the spotlight due to the heavy environmental impacts along their products’ life cycle and, at the same time, they are a priority sector in the new circular economy action plan of the European Commission. In this framework, we have developed a value chain based on the recycling of pre- and post-consumer discarded textiles, which output is a secondary wool fiber named MWool®. After years of assessments and in-depth studies, we managed to achieve a certified Life Cycle Assessment calculation for our MWool® fibers and fabrics. Our study, in collaboration with the prestigious Politenico di Torino, develops an environmental analysis of recycled wool fibers through the Life Cycle Assessment (LCA) methodology. A parallel LCA is developed for virgin wool fibers too, in order to obtain a data-based comparison. Deep analyses have been carried out to capture the uncertainty associated with virgin fibers’ impacts and to evaluate how MWool® impacts vary according to the origin and treatment of recycled textiles. Finally, the Circular Footprint Formula (CFF) has been applied to consider also a possible decay in quality typically affecting recycled fibers, and it emerges that recycled wool fibers can save about 60% of the impacts of virgin fibers. . Results show that recycled wool fibers have significantly lower environmental impacts than virgin fibers, even when the most unfavorable scenarios are considered.