A steel sheet comprising, as a chemical composition, by mass%: C: 0.05% to 0.25%; Si: 0.05% to 2.00%; Mn: 1.50% to 3.00%; Al: 0.005% to 1.500%; P: 0% to 0.040%; S: 0% to 0.010%; N: 0% to 0.0100%; O: 0% to 0.0060%; Cr: 0% to 0.50%; Ni: 0% to 1.00%; Cu: 0% to 1.00%; Mo: 0% to 0.50%; Ti: 0% to 0.200%; Nb: 0% to 0.200%; V: 0% to 0.500%; B: 0% to 0.0100%; W: 0% to 0.1000%; Ta: 0% to 0.1000%; Sn: 0% to 0.0500%; Co: 0% to 0.5000%; Sb: 0% to 0.0500%; As: 0% to 0.0500%; Mg: 0% to 0.0500%; Ca: 0% to 0.0400%; Y: 0% to 0.0500%; La: 0% to 0.0500%; Ce: 0% to 0.0500%; Zr: 0% to 0.0500%; and a remainder: Fe and impurities, wherein when a sheet thickness is denoted by t, a metallographic structure at a t/4-position, which is a position t/4 away from a surface, in a cross section in a sheet thickness direction includes, by volume percentage, ferrite: 20% or greater, bainite and martensite: 40% or greater in total, and a remainder consisting of one or more selected from residual austenite and pearlite, when a Mn concentration is measured at a plurality of measurement points at intervals of 1 μm in a square region with a side length of t/4 centered at the t/4-position in the cross section in the sheet thickness direction, a proportion of measurement points at which the Mn concentration is 1.1 times or greater an average of the Mn concentrations at all of the plurality of measurement points is less than 10.0%, a tensile strength is 980 MPa or greater, and a product of the tensile strength and a total elongation is 10,500 MPa % or greater, and wherein the metallographic structure, the Mn concentration, the tensile strength, and the total elongation are measured as described in the description. C: 0.05% to 0.25%; Si: 0.05% to 2.00%; Mn: 1.50% to 3.00%; Al: 0.005% to 1.500%; P: 0% to 0.040%; S: 0% to 0.010%; N: 0% to 0.0100%; O: 0% to 0.0060%; Cr: 0% to 0.50%; Ni: 0% to 1.00%; Cu: 0% to 1.00%; Mo: 0% to 0.50%; Ti: 0% to 0.200%; Nb: 0% to 0.200%; V: 0% to 0.500%; B: 0% to 0.0100%; W: 0% to 0.1000%; Ta: 0% to 0.1000%; Sn: 0% to 0.0500%; Co: 0% to 0.5000%; Sb: 0% to 0.0500%; As: 0% to 0.0500%; Mg: 0% to 0.0500%; Ca: 0% to 0.0400%; Y: 0% to 0.0500%; La: 0% to 0.0500%; Ce: 0% to 0.0500%; Zr: 0% to 0.0500%; and a remainder: Fe and impurities, wherein when a sheet thickness is denoted by t, a metallographic structure at a t/4-position, which is a position t/4 away from a surface, in a cross section in a sheet thickness direction includes, by volume percentage, ferrite: 20% or greater, bainite and martensite: 40% or greater in total, and a remainder consisting of one or more selected from residual austenite and pearlite, ferrite: 20% or greater, bainite and martensite: 40% or greater in total, and a remainder consisting of one or more selected from residual austenite and pearlite, when a Mn concentration is measured at a plurality of measurement points at intervals of 1 μm in a square region with a side length of t/4 centered at the t/4-position in the cross section in the sheet thickness direction, a proportion of measurement points at which the Mn concentration is 1.1 times or greater an average of the Mn concentrations at all of the plurality of measurement points is less than 10.0%, a tensile strength is 980 MPa or greater, and a product of the tensile strength and a total elongation is 10,500 MPa % or greater, and wherein the metallographic structure, the Mn concentration, the tensile strength, and the total elongation are measured as described in the description.