At the global level, voices are growing to criminalise severe environmental destruction as ecocide so that the International Criminal Court can punish. This social phenomenon suggests that international criminal law has been ineffective in protecting the environment and humanity at the time of planetary crisis. In parallel, however, only a small body of literature exists looking at how criminal justice is effective in preventing environmental damage at the domestic level. To address this research gap, this study first builds a green criminological perspective, which emphasises crimes of the powerful, and explains different types of ecocide. Then, it examines Korean environmental criminal law and demonstrates that high-level personnel in corporations have not been adequately held accountable for serious environmental destruction. As a viable option to strengthen criminal justice in the environment sector in Korea, it is argued that the Serious Accidents Punishment Act (SAPA) can be amended to hold business owners and other responsible persons accountable and liable for serious environmental crime caused by corporate activities.