We perform investigations on the structural, electronic, and magnetic properties of vanadium-stacked benzimidazole-modified single-stranded DNA (sDNA) using density functional theory. We find that the vanadium atoms aligned along the helical axis interact ferromagnetically. Furthermore, under the influence of an external electric field, these one-dimensional ferromagnets show half-metallic behavior, with the closing of the spin gap in the minority spin channel. The half-metallic behavior of these systems crucially depends on the hybridization of the vanadium valence orbitals in the stacking direction. Also, we show that the sugar-phosphate backbone does not influence the magnetic interactions, making the modified sDNA scaffold ideal for advanced spintronics applications.