<p>This study examines how corporate social responsibility improves sustainable business performance in Vietnamese manufacturing firms by clarifying the capability mechanisms and contextual conditions involved. Grounded in stakeholder theory and the resource-based view, the research develops and tests a structural model using survey data from 558 middle- and senior-level managers across quality, environmental management, research and development, and production units. The findings show that corporate social responsibility significantly promotes green intellectual capital and green ambidextrous innovation. Green intellectual capital functions as a major catalyst for green ambidextrous innovation and acts as a central pathway translating corporate social responsibility into enhanced sustainable business performance. Green ambidextrous innovation also mediates the effect of corporate social responsibility on sustainable business performance, underscoring its value as a strategic innovation capability. Furthermore, green absorptive capacity strengthens the positive impact of green ambidextrous innovation on sustainable business performance, while cultural workforce diversity further amplifies this relationship by enriching knowledge flows supporting innovation. The study advances understanding of how corporate social responsibility shapes sustainable business performance through knowledge- and innovation-based capabilities, and it identifies key moderating factors that reinforce these effects. The results offer practical implications for managers seeking to leverage green knowledge, innovation capacity, and culturally diverse human resources to achieve sustainability goals.</p>