With increasing global climate change, integrated concepts to innovate sustainable structures that can multiaxially address CO2 mitigation are crucial. Here, we fabricate a functional wood structure with enhanced mechanical performance via a top-down approach incorporating a high-performance metal-organic framework (MOF), Calgary framework 20 (CALF-20). The functional wood with 10% (w/w) CALF-20 can capture CO2 with an overall gravimetric capacity of 0.45 mmol/g at 1 bar and 303 K that scales linearly with the MOF loading. Interestingly, the functional wood surpasses the calculated normalized adsorption capacity of CALF-20 stemming from the mesoporous wood framework, pore geometry modulation in CALF-20, and favorable CO2 uptake interactions. Density functional theory (DFT) calculations elucidate strong interactions between CALF-20 and the cellulose backbone and an understanding of how such interactions can favorably modulate the pore geometry and CO2 physisorption energies. Thus, our work opens an avenue for developing sustainable composites that can be utilized in CO2 capture and structural applications.