Climate risk increasingly shapes corporate sustainability decisions, yet its role in business strategy and environmental, social, and governance (ESG) performance remains underexplored. This study examines how prospector versus defender business strategies influence ESG performance, moderated by climate risk, using panel regressions on 2756 firm-year observations from publicly listed firms in Indonesia, Malaysia, the Philippines, Thailand, and Vietnam (2009–2024). Findings reveal that prospectors exhibit significantly lower ESG performance than defenders under both normal conditions and heightened climate risk. These results extend dynamic capability theory by demonstrating strategic deployment differences: Prospectors prioritize innovation and market expansion over ESG adaptation, whereas defenders emphasize stability and compliance under uncertainty. The study contributes to the literature by incorporating climate risk as a contextual factor shaping the strategy–ESG relationship. Acknowledging limitations in ESG data coverage, future research should explore strategies focused on climate mitigation and adaptation to better capture sustainability dynamics amid climate uncertainty. © 2026 ERP Environment and John Wiley & Sons Ltd.