This study investigates the integration of Environmental, Social, and Governance (ESG) principles into corporate strategy amo ng New Zealand businesses, focusing on their responses to climate-related risks. Despite the global proliferation of ESG research, evidence from small, open economies like New Zealand remains limited, particularly in the context of recent regulatory mandates such as the 2023 mandatory climate-related financial disclosures introduced by the Financial Markets Authority (FMA). Using a mixed-methods approach, the study combines quantitative analysis of ESG scores, disclosure indicators, and financial performance metrics for NZX-listed firms between 2018 and 2025 with qualitative multiple case studies across the energy, agriculture, and finance sectors. Results reveal a positive relationship between ESG integration and financial outcomes, including return on assets, market valuation, and operational resilience. Sectoral analyses indicate that technology and finance firms exhibit the highest ESG maturity, while agriculture and energy sectors demonstrate moderate adoption, often constrained by resource limitations and compliance-driven approaches. Qualitative findings highlight the critical role of governance mechanisms, stakeholder engagement, and strategic alignment in converting ESG adoption into meaningful organizational benefits. The study identifies regulatory frameworks, dynamic capabilities, and internal governance as key enablers of effective ESG integration, while emphasizing that early adoption provides a competitive advantage in managing climate risks. Limitations include reliance on secondary ESG data and a focus on publicly listed firms, suggesting the need for future research encompassing SMEs and longitudinal analyses. Overall, the study contributes to the understanding of ESG integration in small, open economies and offers practical insights for policymakers and corporate managers seeking to enhance resilience and sustainable value creation in the face of climate change.