Junko Saotome is a major supporting character who serves as the closest friend and confidante of Nana Komatsu. Junko and Nana first met during their first year of high school, where they were in the same class and both joined the art club, eventually becoming best friends by the time they graduated. Following high school, Junko enrolled in Naruse Art School, taking her artistic pursuits seriously, which led her to apply and gain acceptance to an art college in Tokyo. Her background includes a rebellious streak from her middle school years, where she was known to have run with a gang, an experience that contributes to her fearless and grounded demeanor.

In terms of personality, Junko is defined by a practical and sensible nature. She operates with a no-nonsense policy when dealing with people and exhibits a level of emotional maturity that far exceeds her age, often making her seem like a maternal figure to her more impulsive friend. While she can be blunt and her advice is often pointedly honest, this sternness is balanced by a deep sense of care and loyalty toward the people she values. Her approach to friendship is frequently described as tough love; she is quick to scold Nana for naive decisions but is equally present to console her and offer steadfast support. She is also described as a reliable and understanding individual who acts as a strong pillar of support for her friends.

Junko is motivated by a clear vision for her own life, approaching her education and future career with a level of dedication that contrasts with Nana’s more romantic and chaotic pursuits. Her role in the story is primarily that of a grounding force and a voice of reason. Within the group of friends from her hometown, she often acts as pragmatic advisor, providing critical and realistic perspectives on relationship and career troubles. Her home and the local bar Jackson Hole serve as regular gathering spots for the friend group, positioning her as a central figure in the social circle that connects Nana Komatsu, Shoji Endo, and her boyfriend.

Regarding her key relationships, Junko shares one of the longest and most stable partnerships in the series with Kyosuke Takakura. They were introduced by a mutual friend, Shoji, and began a relationship that quickly settled into a dynamic often compared to that of an old married couple, eventually leading them to live together in Tokyo. Her friendship with Nana Komatsu is the cornerstone of her character; Junko often takes on a protective, mother-like role as she watches over Nana’s tumultuous journey into adulthood. Junko is also friends with Shoji Endo, having known him since middle school, and she strives to remain neutral when conflicts arise between him and Nana.

Throughout the narrative, Junko’s development is seen in her consistent pursuit of independence and artistic success. She balances school, a part-time job at a clothing store, and her personal relationships with a sense of stability that many other characters lack. As the story progresses and Nana matures, Junko remains her most trusted confidante, one of the few people to whom Nana can truly open up. Notably, Junko hosts the bonus pages at the end of manga volumes, where she reads fan mail and displays fan art. Her notable abilities include a high level of artistic skill, particularly in painting, which she pursues as a professional and academic focus, and a strong, practical intelligence that allows her to navigate urban life and personal challenges successfully. She is also characterized by her distinct physical traits, including her tall stature, tan skin, and multiple ear piercings, and her style is described as a mix of funk and bohemian.