Lucky Star, also called the Original Lucky Man, is a cosmic superhero entity originating from outer space. Before encountering Yoichi Tsuitenai, it reigned as the cosmos's luckiest and strongest superhero, though not constantly engaged in alien conflicts. Its distinct appearance features gray skin, glowing yellow eyes, and a taller, skinnier adult frame compared to the fused Luckyman form. Alien symbols adorn its chest, differing from Luckyman's kanji "大吉" (Daikichi).

Observing Earth during a critical moment, Lucky Star witnessed an alien spaceship crush Yoichi to death and the immediate threat a mantis-like alien posed to Miyo and the town. Intervening, it faced an initial physical attack from Yoichi, angered by the perceived threat to Miyo. This encounter unexpectedly triggered a permanent fusion between Yoichi's spirit and the Lucky Star entity, merging them into the singular superhero Luckyman. This fusion granted Yoichi the power to transform into Luckyman, wielding ultimate good luck, though he reverts to his unlucky human form after brief victories.

The entity's power is intrinsically linked to a celestial body known as the Lucky Star. For Luckyman's extraordinary good fortune to manifest, the shining star's light must reach him. Consequently, Luckyman loses his powers and becomes extremely vulnerable if clouds, rain, or anything obscures the Lucky Star's light.

Following the fusion, Lucky Star ceased to exist as a separate entity, its consciousness and power permanently combined with Yoichi within Luckyman. Before departing in the anime adaptation, it provided Yoichi with a jar of special pickled garlic cloves (rakkyō), each infused with the power to trigger his transformation into Luckyman when needed.

Prior to meeting Yoichi, the original entity worked as a convenience store clerk, indicating a life beyond constant superhero duties before the pivotal fusion.