The electronic structure of BaBiO3 and Ba1−xKxBiO3, where x = 0.375, 0.4, and 0.425 is investigated using the density functional theory (DFT) in the generalized gradient approximation (GGA). The charge-density-wave (CDW) nature of the host compound is suppressed via potassium doping at Ba-site, resulting in the emergence of a metallic state. A strong hybridization between Bi-6s and O-A1g orbitals is observed in the electronic states near the Fermi level, particularly enhanced in the collapsed BiO6 octahedra of the undoped compound. The K-doped systems show stronger spσ hybridization than that of the host compound. The self-doped holes condensate in the antibonding combination of Bi-s and O-A1g orbitals of both the doped systems and in the collapsed octahedra of the undoped system. The exploration of lattice dynamics and electron–phonon coupling in Ba1−xKxBiO3 systems, elucidate that mainly the phonons corresponding to the oxygen bond stretching vibrations contribute most to the total electron–phonon coupling. The GGA-calculated electron–phonon coupling constants (λ) across varying K-concentrations inadequately account for experimental Tcs. The inclusion of long-range interactions through the HSE06 hybrid exchange–correlation functional substantially augments both λ and Tc, closely mirroring experimental observations and underscoring the crucial role of nonlocal correlations in these systems.