Our society is now entering the “age of the environment.” To address challenges such as climate change and resource constraints, we need not only technological development but also innovative business models that harness market mechanisms. The Green Business Laboratory focuses on green business and the circular economy, analysing the relationship between corporate activities and the environment and designing systems that contribute to a sustainable society. Our research encompasses emissions trading, renewable energy, ESG investment, environmentally friendly products and services, and resource-circulating industries, including recycling, reuse, and remanufacturing. Although green business poses many challenges, Japan’s technological capabilities and experience provide opportunities to lead the world. Together with students, we explore and practice these opportunities from the perspectives of policy, economics, and technology.