To promote the sustainable development of supply chains, numerous manufacturers are embracing corporate environmental responsibility to mitigate the ecological consequences of production activities. The environmental benefit concern (EBC) of enterprises not only affects their operations strategies but also impacts other enterprises within the supply chains. Therefore, it is essential to study the influences of EBC behaviors on supply chain performances under various competitive scenarios. This paper examines a supply chain comprising two manufacturers and one retailer under two distinct competitive settings: Competition between non-green and green products (OE), and competition between green products from small and big brands (SB). The study analyzes the effects of unilateral, bilateral or multilateral EBC behaviors on both the economic and environmental benefits of the supply chain. Key findings emerge from this study. Firstly, prioritizing environmental benefits throughout the supply chain has the potential to enhance environmental performance. Secondly, unilateral EBC behavior can lead to a vertical altruistic effect, where the focus on environmental benefit by a manufacturer (retailer) increases the retailer's (manufacturer) profit but reduces its own profit. Additionally, unilateral EBC behavior among manufacturers creates a competitive squeezing effect on each other, potentially diminishing competitor profits. Notably, the retailer's focus on environmental benefit can also reduce the profit of the non-green manufacturer. Thirdly, when the levels of EBC are relatively low, bilateral or multilateral through EBC leads to a positive effect on economic performance, resulting in increased profits for both the green manufacturers and retailer. In conclusion, bilateral EBC has the potential to enhance both economic and environmental benefits in the OE scenario.