Ginji Kawai is Sasami Kawai's father and Honoka Kawai's devoted husband, consistently prioritizing family closeness over high-profile careers promising fame or riches. This stands in contrast to Shigeki Amano, who pursued overseas work over family presence, leading Misao Amano to envy Sasami's involved and fun father. Ginji operates a distinctive yellow motorcycle with a sidecar, often transporting Sasami to school, and exhibits eccentricities like saying "Good night" in the morning simply because he enjoys the phrase. His profession is intentionally vague, described by Sasami only as doing "all kinds of things." His revealed qualifications include a Class A International Driver's License, certification for unlimited operation of two-wheeled vehicles, qualifications for Class 2 plane operations, NASA astronaut certification, rank 3 in the Japanese Abacus Federation, and past service on a SWAT team demonstrating hand-to-hand combat proficiency. He actively involves himself in Pretty Sammy's activities without magical abilities, initially investigating and recording her battles with a camera, unaware of Sasami's identity. He supports her during events, playing electric guitar and advising her to defeat the "Pro Karaoke Girl" Love-love Monster through singing. During a volcanic eruption trapping them on an island, he builds a raft for rescue. He intervenes in crises using practical skills: throwing shuriken to disable a revolver, manipulating six water hoses simultaneously to extinguish a fire, and bypassing a magical barrier by professing love to the "Break-Up Girl" monster, triggering Honoka's jealousy. Later, he infiltrates Umi no Hoshi Elementary to aid Pretty Sammy against the Lovely Madams, deploying "Dandy Power" as a distraction. Collaborating with Washu under codenames "Johnny" (himself) and "Catherine" (Washu), he pilots Washu's rocket to Juraihelm using his NASA credentials but loses control during launch due to excitement. After crashing, he remains determined to complete the mission. In the finale, he explicitly acknowledges Sasami as Pretty Sammy, expressing confidence in her ability to save Earth, and later retrieves Sasami and Misao from space. The Kawai residence includes a CD Vision store run by Honoka, though Ginji notes declining sales due to her neglect for video games, suggesting a cash box system for unsupervised transactions. The house also contains a basement unknown to Sasami, housing a butler named Alfred and a "Sammy-Mobile" used for magical emergencies.