Gentou Nogizaka, father of Haruka and Mika and president of the affluent Nogizaka family conglomerate, cuts an imposing figure with a stern demeanor and yakuza-inflected speech. He commands the elite paramilitary unit "Hell Hound," utilizing it for surveillance and tactical operations. Beneath this intimidating exterior lies fierce devotion to his daughters, expressed through grand gestures like acquiring an entire island for Haruka's birthday.

Initially oblivious to Haruka's secret otaku pursuits, Gentou reacts with vehement disapproval upon discovery, confiscating her anime merchandise and launching a military assault on Yuuto Ayase's residence to retrieve her. Only his wife Akiho's intervention forces his retreat. His protectiveness manifests as exaggerated suspicion toward anyone near Haruka, particularly Yuuto, whom he routinely accuses of dishonorable motives. Gentou frequently disrupts their interactions, misconstruing innocent scenarios as compromising.

Akiho Nogizaka alone quells his outbursts, reducing him to fearful compliance often followed by sulking. Despite this dynamic, Gentou gradually develops reluctant respect for Yuuto after witnessing the boy's defiance during clashes over Haruka's hobbies and safety. His hostility evolves into conditional tolerance of her interests, though overprotective interventions persist.

In the series finale, Gentou participates in an orchestrated test of Yuuto's commitment, overwhelming him in a physical confrontation. Yuuto's unwavering resolve to reach Haruka ultimately convinces Gentou of his genuine devotion, securing acceptance of their relationship. This resolution underscores his role as a doting father prioritizing his daughters' happiness behind an austere facade. Gentou adopted the Nogizaka surname upon marrying Akiho, reflecting the family's matrilineal prominence.