Ino is the only child of Yamanaka Inoichi and was a popular student during her time in the Academy. There, she met Sakura Haruno, who was teased by other kids due to her large forehead. Ino defended Sakura from her bullies and encouraged her to embrace her forehead rather than hide it, becoming good friends with her.
Over the following years, Ino's guidance and friendship helped Sakura become more confident and develop into her own person. A while later, Ino and Sakura got closer to Senju Haru at the Academy, when they were put into a group for a school work together. The three quickly became very close friends and were always together. At the time, the three made made a promise that they'd always be together, simbolizing the friendship between the trio. They would always go to each other houses to play, train, or eat lunch together.
One day approximately five years ago, Ino, along with Nara Shikamaru and Akimichi Choji were stealing bits of food from others for a mysterious child named Yota. During this time, Sakura began to feel that she was in Ino's shadow and longed to prove herself as Ino's equal.
When Sakura found out that Ino also had a crush on Uchiha Sasuke, Sakura ended their friendship so that they could compete for Sasuke's love, not realizing this would deeply hurt Ino, thus beginning a bitter rivalry between the two, which later ended when Sakura apologized to Ino and they reconcealed.
From a young age, Ino has been confident, friendly, bold, and outspoken, occasionally lashing out at others if their personal habits bother her. She is generally more motivated than her teammates Shikamaru Nara and Choji Akimichi and tends to take charge of them. Shikamaru, despite finding most girls "troublesome", typically offers no resistance to Ino's forceful behavior, being unwilling to deal with her reaction if things don't happen her way. She is also prideful in her appearance and often tries to lose weight by dieting in the hopes that it will make her more attractive to boys; she even jokingly suggests that Choji should do the same to attract girls. Ino is quite knowledgeable about different types and meanings of flowers, sometimes making analogies to them when talking.
Despite her assertiveness, Ino is a compassionate and kind individual at heart, having been raised to embody the meaning of the bush clover: a blunt, candid love who treasures the bonds with her friends. It is these qualities that earned Sakura Haruno's friendship, defending Sakura from her bullies who teased her and assisted in helping her become confident. Their warm friendship developed into a bitter rivalry over the following years, fueled by competition of Sasuke's affections, ninjutsu and even trading insults, with "Ino-pig" and Sakura as "Forehead Girl". After the Chunin Exams, Ino becomes impressed by Sakura's growth and they rekindle their friendship, while maintaining their rivalry on more amiable terms. She cares greatly for her teammates as well, being relieved that they survived after the failed Sasuke Recovery Mission, encouraging them to stay strong in the face of danger. By the time of his death, Inoichi believed that Ino had truly blossomed into the bush clover of the Yamanaka Clan, and is proud of her bonds with her friends.
Ino had the same infatuation on Sasuke that most other girls in their Academy class had, due to his good looks and cool personality. Even after Sasuke defection from Konoha, Ino largely retained her feelings for him in Part II: she cried when he was declared an international criminal, and pictured him as the "love" the bush clover symbolises during the Fourth Shinobi World War. Ino meets Sai in Part II: who not only replaces Sasuke on Team 7, but also strongly resembles him in appearance. For this reason, Ino becomes immediately smitten with him, flirting with him when first introduced and blushing when Sai calls her beautiful. Although her Infinite Tsukuyomi dream reveals she likes the idea of Sasuke and Sai fighting over her, Ino's affections ultimately shift towards Sai, showing a deeper desire to know more about him as she risks her life to save him in Shikamaru Hiden.
Ino has fair skin, blue eyes (sometimes seen as green in the manga), and long platinum blonde hair worn in a ponytail, with bangs framing the right side of her face. Her hair is seen in different lengths: in Part I, her ponytail extends to her waist, but it is later cut and grows to shoulder-length; in Part II, the bangs grow to cover half of her face, her ponytail becomes waist-length, and she sports a red clip on the left; in the The Last: Naruto the Movie, her hair hung loosely and extends to her calves; as an adult, her hairstyle returns to its shape in Part II, except that her ponytail reaches her upper-back and sports a black clip. In Part II: Sai mentions that Ino is very beautiful.
Ino regularly wears a purple outfit consisting of a high-collared blouse and matching apron skirt. In Part I, she sports this attire with bandages on her abdomen and upper legs, small hoop-earrings, her forehead protector worn as a belt, and for a time, white arm warmers with purple trimmings. In Part II, Ino's outfit is slightly more revealing as she discards her forehead protector and bandages while exposing her midriff and wears mesh armour on her thighs, elbows, and knees. She also replaces her hoop earrings with studs, a gift from Asuma Sarutobi. During the Fourth Shinobi World War, Ino dons the standard Konoha infantry flak jacket and assorted clothing. In The Last: Naruto the Movie, she wears a longer skirt that reaches her ankles, high-heeled sandals and pink lipstick. As an adult, Ino wears a purple outfit once again exposing her midriff with one mesh armour on her left arm and open-toed sandals. She also dons the standard Konoha uniform while on missions.