Wood is recognized as an attractive alternative to several traditional building solutions, and it is often called a “building material of the 21st century” since it can efficiently sequester carbon, balancing emissions from other materials. As a biological material, wood is sensitive to environmental conditions and microorganisms; therefore, it requires protective measures to extend its service life in outdoor applications. Despite the current demand for improvement of wood performance and considering technologies with low environmental impact, there is limited research on treatments and formulations that use green alternatives and improve critical properties simultaneously. The ambition of the MULTI-WOOD project is to provide multi-functional treatments to entirely protect wood from nano- to microscale using alternative sources of chemicals generated during the lignocellulosic bioconversion and/or from the pulp and paper industries. The project aims to develop innovative strategies for the improvement of four key wood properties: hygroscopicity, resistance against fire, UV, and biotic factors based on alternative, recently underutilized bio-based formulations. Proposed methodology and treatments target reduction in the toxicity of the modification processes, extend service life, elongate maintenance cycles, and thus, lower the negative impact on the environment. The MULTI-WOOD project will stimulate innovation and knowledge transfer between the host and ER by building a solid research and industrial network, organizing events, mentoring young researchers and managing projects, the ER will gain research and scientific skills and acquire a new set of competencies to reach professional maturity and independence after the fellowship.