As the urgency and importance of global carbon emission reduction have escalated in recent years, numerous firms are considering ideas to develop innovative green technologies in order to contribute to the low-carbon economy. This paper examines two types of green innovations adopted by firms, namely process innovation (improving production processes to enhance energy efficiency) and recycling innovation (establishing a circular economy to recycle and re-manufacture waste products). By developing a game-theoretical model, our analytical results reveal the following findings. First, we find that both process and recycling innovations can attract more consumers and improve the firm’s profitability under specific conditions. Second, when the cost advantage of remanufacturing is sufficiently low, the adoption of process innovation is always more profitable than recycling innovation. Otherwise, the profitability largely depends on the trade-off between consumers’ perception of the two green innovations. Third, compared to a single innovation, the adoption of both process and recycling innovations (dual green innovation) leads to a further increase in consumer demand and firm’s profit when the cost advantage of remanufacturing exceeds a certain threshold. Furthermore, the optimal pricing set by the firm and consumer demand become more sensitive to consumers’ perception of greenness when dual green innovation is adopted. Finally, the equilibrium result suggests the existence of a “synergistic promoting effect” when the firm implements dual green innovation, which indicates that the advantages of each innovation are amplified when the firm adopts dual green innovation. These results can serve as guidelines for firms aiming to utilize green innovations in order to reduce carbon emissions.