Based on the contingency, transaction, and trust theories, this paper explored how the green cooperation between supplier and customer in last-mile logistics contributes to consumers’ sustainable consumption behaviors and trust and transaction cost's contingency role. We collected survey data from 453 users of green shopping platforms in South Korea (e.g., Homepick and Smart Locker) and analyzed the data using structural equation modeling. The results suggest that green cooperation with companies positively affects consumers’ sustainable consumption behaviors and trust, and transaction costs negatively moderate such relationships. In addition, customer trust positively affects sustainable consumption behavior and loyalty. We also found that improved sustainable consumption behavior can form loyalty, but transaction cost decreases its positive impact. This paper evaluates the last-mile delivery through green cooperation and enriches the literature on contingency, transaction cost, and trust theories.