Sustainable entrepreneurship refers to the economic, social, and environmental value creation across enterprises in Malaysia. When examining sustainable entrepreneurship in Malaysian companies, small and medium-sized enterprises (SMEs), which serve as the backbone of the Malaysian economy and account for 97.2% of businesses and generate 38.2% of the gross domestic product, cannot be overlooked. The research is the first study in Malaysia, which extends the entrepreneurial event model to develop a comprehensive research framework to examine and propose suggestions to improve sustainable entrepreneurship in SMEs. A questionnaire was distributed to 400 entrepreneurs from SMEs in central regions in Malaysia, and 300 complete and valid questionnaires were used for the analysis. All constructs in the questionnaire were tested and confirmed to have high convergent validity and high composite reliability. The results show that perceived desirability, perceived feasibility and propensity to act have a positive effect on sustainable entrepreneurship in SMEs. Young entrepreneurs under 40 years old show greater propensity to act on sustainable entrepreneurship compared to older entrepreneurs aged over 40 years old. This research offers practical and theoretical new insights for SMEs, entrepreneurs, employees, and institutions toward improving sustainable entrepreneurship in a developing nation in Asia.