A recent trend towards sustainability has led to increases in various sustainable practices, but sustainability has still not been fully implemented into manufacturing and supply location decisions. A fragmented product supply chain, which has various locations and multi-tier suppliers, leads to difficulties in traceability to ensure the supply chain has business, environmental, and social/socio-economic sustainability, known as the triple bottom line (TBL).

Thus, this thesis aims to reveal which manufacturing decisions and location configurations better contribute to TBL, as well as to develop a location decision-support model for designing or evaluating multi-tier supply chains with objective measurements and TBL factor considerations. Mixed methods are employed, including systematic literature reviews, semi-structured interviews, and supply chain simulations for the model formulation and its viscose t-shirt application. The thesis highlights that TBL benefits of proximity and distant manufacturing are location-dependent with their sources from spatial, cultural, ethnic, and linguistic proximity as well as country-, supplier-, and firm-specific. Spatial proximity benefits can be from proximity manufacturing to markets, materials suppliers, and headquarters as well as proximity between headquarters and market.

The propose model has the potential to reveal the lowest or optimized cost and carbon dioxide equivalent (CO2e) SCs. The model is capable of revealing important factors and possible risks from future local and global disruptions, benefiting long-term supply chain planning. The model differentiates itself from the others by incorporating TBL from not only manufacturing and logistics activities but also sustainability assurance activities performed by suppliers and focal firms. The model potentially helps enhance TBL sustainability and supply chain visibility. This thesis has theoretical contributions to location theories, manufacturing decisions, cost and CO2e computational models, and sustainable multi-tier supply chain management.