Small and medium-sized firms of diverse categories, including production and services, are significant for Malaysian economic growth. The SME sector contributes to economic growth, employment and financial stability but similarly brings several challenges, specifically environmental concerns. Malaysian SMEs are facing several issues related to the scarcity of resources, capabilities and abilities of firms to address the burning issue of environmental sustainability as it has gained attention due to amplified global warming and increased air pollution. This research focused on environmental sustainability in the Malaysian SME sector due to its significant contribution and potential effects on the environment and global warming. The researcher argued that appropriate culture and leadership should be incorporated in predicting environmental sustainability. This study coined the formative variable of organizational culture and responsible leadership in predicting environmental sustainability. Women business owners are focused on firms governed by females and are much more responsive towards environmental concerns. The study also contributed to the body of knowledge by expressing the role of environmental passion in determining environmental sustainability. The purposive sampling technique was applied to collect data from respondents of the SME sector as the study context was Malaysian SMEs of diverse categories and from different regions of Malaysia. The collected data was assessed through Smart-PLS, the variables were found to be reliable and valid for the context of the study, and the structural equation modeling technique was applied to assess hypothesized relationships. The findings of the study reported that direct hypotheses such as hypothesis H1, which determined the relationship between organizational culture and environmental sustainability, were supported; hypothesis H2, which determined the significance of the relationship between responsible leadership and environmental sustainability; and H3 hypothesized the relationship between environmental passion and environmental sustainability was also reported as significant. The H4 and H5 hypothesized relationships determined the moderation effect of environmental passion between exogenous and endogenous constructs. The insignificant moderation effect of environmental passion was reported.