Insoles provide resistance to ground reaction forces and comfort during walking. In this study, a novel weft-knitted spacer fabric structure with inlays for insoles is proposed which not only absorbs shock and resists pressure, but also allows heat dissipation for enhanced thermal comfort. The results show that the inlay density and spacer yarn increase compression resistance and reduce impact forces. The increased spacer yarn density provides better air permeability but reduces thermal resistance, while a lower inlay density with a random orientation reduces the evaporative resistance. The proposed structure has significantly positive implications for insole applications.