Akemi Roppongi is a resident of room six at the Maison Ikkoku boarding house. Her primary occupation is working as a hostess or bartender at a nearby bar called Cha-Cha Maru. Because she works the late-night shift and often stays out drinking afterward, she has a perpetually sleepy or drowsy expression and is frequently seen around the boarding house during the day in revealing lingerie or a nightgown, seemingly unconcerned about the other tenants' opinions.

Akemi possesses a confident, world-weary, and sexually liberated personality. She is generally calm and stylish, but also prone to laziness and drinking heavily with her neighbors. While she can be aloof towards the main protagonists, Yusaku Godai and Kyoko Otonashi, she is not above participating in schemes to tease or torment Godai, often alongside her fellow tenant, Yotsuya. She enjoys provoking Godai by tempting him with her body, only to slap him if he stares, a tactic she especially enjoys employing when Kyoko is present to make Godai appear more perverted. However, compared to other tenants like Yotsuya or Mrs. Ichinose, her torment is typically less harsh, and she occasionally shows a quiet, understated support for Godai's struggles and romantic efforts.

Beneath her tough and carefree exterior, Akemi is a sensitive woman who has had poor luck in love. It is revealed that she has experienced significant heartbreak in the past, including one relationship so devastating that she contemplated suicide. This hidden vulnerability allows her to understand the feelings of both Godai and Kyoko, and she often provides a grounded, worldly perspective on their situations. Her role in the story is largely that of a chaotic, meddling neighbor, but she also serves as a foil to Kyoko. While Kyoko begins the series as naive and reserved, Akemi is experienced and bold, and their interactions gradually cause Kyoko to become more assertive and self-assured.

Akemi has a close, alcohol-fueled friendship with Hanae Ichinose and the mysterious Yotsuya. The three of them frequently hold impromptu drinking parties in Godai's room, gossiping and interfering in his private life. She spends a significant amount of time with Yotsuya in particular, and the two enjoy teaming up to spy on Godai and create trouble for him and Kyoko. Although Yotsuya seems to be attracted to her and spies on her through a hole in the wall, their relationship remains non-romantic and based on shared mischief. Akemi also displays a blatant and unapologetic sexual interest in Shun Mitaka, Godai's wealthy rival for Kyoko's affections. She frequently flirts with him and clings to him, despite being fully aware of his feelings for Kyoko, and Mitaka is consistently uncomfortable with her advances.

Throughout the series, Akemi undergoes significant development, transitioning from a seemingly aimless party girl to a settled married woman. At the beginning, her lifestyle suggests a kind of complacency, accepting fleeting affairs and disappointing relationships. By the end of the story, her character arc culminates in her accepting a marriage proposal from her boss, the man known only as the Master of the Cha-Cha Maru bar, and she moves out of the boarding house to live with him. While she does not possess any supernatural or physical abilities, her notable strengths include her sharp observational skills, her ability to remain calm in chaotic situations, and her worldliness, which she uses to subtly guide and influence the other characters. Her exact age is never stated, though remarks made in the series suggest she is in her late twenties.