Minoru Shiraishi serves as both a classmate to Konata Izumi in high school class 3-B, likely eighteen, and the assistant on the "Lucky Channel" segment. His work under Akira Kogami involves enduring frequent verbal abuse and physical violence when he fails her expectations. This relentless mistreatment defines much of his experience. Balancing part-time work, studies, and Akira's abuse leads to intense stress.

Akira once sent him to collect spring water near Mt. Fuji. He returned injured and disheveled, suggesting a bear attack. When Akira rejected the water as too warm and threw it in his face, Minoru snapped. He grabbed her collar, unleashed a furious rant about her chronic cruelty, and proceeded to wreck the "Lucky Channel" set, ending the episode.

Temporarily replaced by Daisuke Ono, Minoru later returned. Unresolved tensions erupted again; he physically attacked Akira, declared his resignation, and rampaged through the studio. He overturned furniture, assaulted staff, and finally smashed the camera while shouting at viewers before the feed cut to static.

Yūko Gotō later mediated a reconciliation. Minoru and Akira resumed co-hosting "Lucky Channel" from the repaired set. The live-action segment of the OVA features Minoru Shiraishi. Generally meek and patient early on, prolonged mistreatment triggers his extreme outbursts of rage. Konata Izumi nicknames him "Sebastian" due to his butler-like demeanor. He also works part-time at a karaoke bar Konata and her friends frequent. The OVA "Lucky Star: Original na Visual to Animation" features Minoru Shiraishi.