Ferrite (α-Fe), as a fundamental phase of steel materials, plays a decisive role in determining their macroscopic mechanical behaviors through its microscopic properties, particularly in engineering applications involving resistance to plastic deformation and fracture, fatigue resistance, wear resistance, and low-temperature toughness. Therefore, alloying elements are commonly introduced to improve the performance of steel via mechanisms such as grain refinement strengthening and precipitation strengthening. However, in these strengthening mechanisms, the effects of doped alloying elements on the stability, electronic structure, and mechanical properties of ferrite itself have not been thoroughly investigated. In this study, orthogonal experimental design and first-principles calculations are employed to investigate the effects of ternary alloy doping with M (Mn, Ti, Mo) on the stabilities, electronic structures, and mechanical properties of a ferrite-based supercell model Fe_16-x-y-zMn_xTi_yMo_z (x, y, or z = 0, 1, or 2), aiming to provide both theoretical insight and experimental reference for improving the comprehensive performance of ferrite-based steels by modifying the properties of the matrix phase. The results of the formation enthalpy (H_form) calculations indicate that all solid solutions have negative formation enthalpies, suggesting that they can form spontaneously. Among them, Ti doping is the most favorable for solid solution formation, followed by Mn, with Mo being the least favorable. The Fe₁₃Ti₁Mo₂ configuration is the easiest to form spontaneously. The cohesive energy (E_coh) results demonstrate that all solid solutions exhibit structural stabilities. Fe₁₃Ti₁Mo₂ has the largest (most negative) cohesive energy of –477.96 eV, indicating that it possesses the highest structural stability. The contribution of Mo doping to stability enhancement is the greatest, followed by Ti, while the influence of Mn is the smallest. Electronic structure calculations reveal that M doping consistently reduces the density of states (DOS) at the Fermi level for Fe_16-x-y-zMn_xTi_yMo_z. The lowest DOS at the Fermi level is found to be 4.294 in Fe₁₃Ti₁Mo₂, indicating enhanced hybridization and overlap between Mn 3d, Ti 3d, Mo 4d, and Fe 3d states. This strong hybridization leads to a decrease in the Fermi level and contributes to the high stability of the Fe₁₃Ti₁Mo₂ phase. Mechanical property calculations indicate that M doping reduces the Young’s modulus (E) and Vickers hardness (H_V) of the solid solutions. However, the K values (K = G_H/B_H) are all greater than 1.75, and Poisson’s ratios (ν) exceed 0.26, implying that while stiffness and hardness decrease, the ductility of the materials is improved. This study provides valuable guidance for designing ductile and tough ferrite-based steel materials.