While the effects of elevated CO₂ (eCO₂) on crops have been extensively studied, cultivar-specific responses and impacts under higher CO₂ concentrations (>800 μmol/mol) remain unclear. Here, we addressed these two aspects to reveal the effects of eCO₂ (approximately 900 μmol/mol) on the yield and quality of three wheat cultivars, Chinese spring (CS), Chuanmai 44 and Neimai 9. The results indicated the net photosynthetic rate (Pn) and water use efficiency (WUEi) of the three cultivars significantly increased under 900 μmol/mol CO₂ concentration. Elevated CO₂ increased the hundred-grain weight (HGW) of Chuanmai 44 (+32.51%, p < 0.05) and Neimai 9 (+8.47% p < 0.05), but had little effect on HGW of CS. CO₂ elevation significantly increased the N content in the grain of CS (+7.27%, p < 0.05). Elevated CO₂ enhanced amino acid biosynthesis in CS but suppressed it in Chuanmai 44 and Neimai 9. No significant changes in grain mineral concentrations occurred in CS and Chuanmai 44 under eCO₂ conditions. Neimai 9 demonstrated significant decreases in K and Mg, with non-significant reductions in other elements. The effects of eCO₂ on grain yield and quality were closely linked to cultivars. This study will provide insights for understanding effects of CO₂ concentration and cultivar interactions on crop growth and selecting wheat cultivar to cope with future climate change.