Climate instability and socio-ecological inequality demand design methodologies that integrate material, biological and cultural systems. While Regenerative, Participatory and biodesign have expanded the scope of design practice, they often lack approaches for integrating material development within culturally situated contexts. This paper introduces Material Re-Mixing, a novel biodesign methodology grounded in place- and culture-based material investigation, biological integration and participatory co-creation. The methodology is developed through a case study in Ulaanbaatar, Mongolia, focusing on bio-composite innovation for traditional wool felt gers. Combining textile testing, biomaterial experimentation, ethnographic research and stakeholder workshops, the case study demonstrates how mycelium-based composites can enhance performance while maintaining cultural continuity and how culturally grounded material investigation and innovation can catalyse systemic healing at the community level. Material Re-Mixing contributes a transferable system that foregrounds material agency, cultural knowledge and circular biological processes, offering a pathway towards more situated approaches to ‘wicked’ socio-ecological challenges (Rittel H and Webber M (1973) Dilemmas in a general theory of planning. Policy Sciences (4), 155–169.).