The ability to enhance environmental performance has emerged as a pivotal corporate strategy for businesses in Malaysia. While the ISO 14001:2015 has been promoted extensively by the Malaysian Department of Standards, its adoption remains low and at a slow pace. There is scarce research to demonstrate the linkage between environmental knowledge, the implementation of life cycle management tools and environmental performance. Therefore, the first aim of this study is to assess the different knowledge levels of respondents on ISO 14001:2015 and four assessment methodologies (i.e., Life Cycle Assessment, Carbon Footprint, Water Footprint, and Material Flow Cycle Accounting). The second aim is to determine whether these knowledge bases contribute to the firms’ environmental performance. A total of 157 ISO-certified firm owners responded to the self-administered questionnaires. A One-Way ANOVA test revealed a difference in knowledge levels, with Life Cycle Assessment having the highest score and Material Flow Cycle Accounting having the lowest. Multiple regression revealed ISO 14001, Material Flow Cycle Accounting, and Carbon Footprint knowledge to contribute to environmental performance significantly. Counterintuitively, Life Cycle Assessment and Water Footprint exerted no significance on environmental performance. Policy implications include information dissemination and training by governmental officials for firm owners and exposure to life cycle management tools.