To achieve carbon neutrality, governments and enterprises are accelerating the decarbonization process in the shipping industry. This paper focuses on the Low-Carbon Maritime Supply Chain (LMSC), considering both government policies and consumers' green preferences. A two-stage Stackelberg game model between shipping companies and freight forwarders is developed to determine optimal pricing and carbon emission reduction strategies, while examining the impacts of carbon taxes, government subsidies, and consumers' green preferences on decision-making. The analysis yields three main findings: First, cooperation between freight forwarders and shipping companies maximizes overall profits for the LMSC; however, to achieve higher emission reduction levels, both parties should co-lead the supply chain. Second, government subsidies and enhanced low-carbon awareness produce dual effects: while they help reduce emissions and increase corporate profits, they may also raise TEU market prices for consumers under certain conditions. Third, although carbon taxes significantly improve the low-carbon performance of the LMSC, they reduce profits for all participants and increase TEU market prices.