KMT-2018-BLG-1990L is a cool M-dwarf (about 0.09 solar masses, 5,778 K), 967 light-years from Earth. KMT-2018-BLG-1990L b is a 0.35-Jupiter-mass companion, at 0.763 AU from its star, discovered in 2019 via microlensing. Microlensing detections occur when a foreground star's gravity briefly magnifies a background source, revealing planets that are otherwise too faint and distant to observe directly. KMT-2018-BLG-1990L b circles its star within the inner habitable zone. At roughly 967 light-years, KMT-2018-BLG-1990L lies far beyond the nearest stars yet remains reachable to large survey telescopes.