All products, including bioproducts, have an impact on the environment by consuming resources and releasing emissions during their production. Biochar, a bioproduct, has received considerable attention because of its potential to sequester carbon in soil while enhancing productivity, thus aiding sustainable supply chain development. In this chapter, the environmental impacts of producing biochar using a holistic method called life-cycle assessment (LCA) or more generally life-cycle analysis are discussed. LCA is an internationally accepted method that can calculate greenhouse gas (GHG) and other emissions for part or all of a product life cycle. The present chapter will show how LCA can assess environmental impacts of the entire supply chain associated with all steps of the biochar system, from biomass harvesting through biochar production to soil amendment, with a focus on the production stage. Exploring a biochar system from a forestry LCA perspective, a new thermochemical conversion technology developed in the United States and used to process waste woody biomass, will be described. In particular, the conversion unit’s environmental performance based on the LCA research conducted so far will be described. Although this chapter will present LCA mostly from a forestry perspective, non-forestry agricultural activities will also be discussed.