Designing lightweight aircraft parts to improve fuel efficiency is crucial to meet the aviation sector’s goals of reducing CO2 emissions. However, it is also important to ensure that these lightweight parts have a lower CO2 footprint over their entire lifetime. Previous studies have successfully achieved this using topology optimization and low-embodied CO2 composite materials. However, it resulted in structures with lower mechanical properties. To address this limitation, a new framework that uses multi-material fibre-angle topology optimization to optimize fibre-reinforced composite structures is developed in this work. This approach optimizes low-embodied CO2 footprint composites and high-performance, high-embodied CO2 composites in the same structure. A comprehensive CO2 footprint assessment of the optimized structures is conducted by varying the amount of each of the two materials in the structure. As a result, a series of multi-material composite structures with varying levels of compromise between stiffness and CO2 footprint are obtained. These findings establish an optimization approach that provides more control over tuning the desired objectives of such structures. In addition, an extensive parametric study is conducted to demonstrate the framework’s robustness. However, during this analysis, certain limitations of the framework are identified, such as difficulties in optimizing fibres and material modelling. To overcome these limitations, a more robust framework can be developed in the future. Additionally, incorporating stress-based topology optimization into the existing framework can also help in achieving further improved designs.