Nanami Nanashiro holds the position of "Number 3" maid in the Nogizaka household, serving as deputy to head maid Hazuki Sakurazaka. She possesses violet hair, black eyes, a height of 1.66 meters, and figure measurements of 85-55-83. Her personality blends cheerful carefree energy with roguish slyness. Though reliable in standard maid duties under Hazuki, she frequently diverts attention to aiding Mika Nogizaka’s schemes to foster romance between Mika’s sister Haruka and Haruka’s classmate Yuuto Ayase. This includes covert spying missions on Haruka and Yuuto, occasionally joined by Hazuki and Haruka’s mother.

Beyond traditional responsibilities, Nanami acts as the family chauffeur. Her driving appears dramatically fast or reckless, yet she retains complete trust in her skills from Hazuki and the household. She consistently engages in key Nogizaka family events involving Yuuto, such as accompanying Haruka and Yuuto to summer Comiket to navigate crowds and secure Haruka’s desired dōjinshi. She joins Mika in defending Haruka’s otaku interests against her father’s disapproval, recruiting Haruka’s mother Akiho as reinforcement. Her matchmaking efforts include accompanying Mika on a disguised "advice-giving" date with Yuuto and observing Yuuto and Haruka dance alongside Mika and Hazuki. She also participates in lighter moments, like a shopping trip where lingerie purchases distract her.

In the OVA *Finale*, Nanami appears in cosplay as Asuna Yuki from *Sword Art Online*, Ran Mōri from *Detective Conan*, and Mikamura Rain from *Mobile Fighter G Gundam* alongside Mika’s Domon Kasshu.