Inoichi Yamanaka

is a Jonin from Konohagakure, and alongside Shikaku Nara and Choza Akimichi, he is a part of the first Ino-Shika-Cho trio.

Background
He is a member of the Yamanaka clan and owns the Yamanaka flower shop along with his daughter Ino Yamanaka. Inoichi is a member of the Ino-Shika-Cho trio, which consists of three Jonin from the Yamanaka clan, the Nara clan, and the Akimichi Clan, respectively. His daughter, Ino, is a member of her own Ino-Shika-Cho, judging that their fathers were once teammates themselves in their early days as ninja.

Chunin Exams
He makes his first appearance during the Chunin Exams' mid-festivals when sitting alongside his two teammates, Shikaku Nara and Choza Akimichi. There he was berated by Shikaku about "how troublesome" it must be to have a daughter.

Later, during the Orochimaru's invasion of Konoha, he along with the rest of the original Ino-Shika-Chou bravely and skillfully fought back the invaders with him demonstrating his impressive mastery of his clan's secret techniques.

Pain Invasion arc
Inoichi was part of Ibiki Morino's Investigation team and tried to read the mind of Pain's henchmen Yūdachi. Tonbo Tobitake, Shimon Hijiri and Mozuku assisted him, but the mind of the henchmen seems to be protected by some sort of powerful genjutsu. He manages to break through the genjutsu protection barrier and go straight into his mind, but he was interrupted when his daughter, Ino, tells him about Konoha being under attack by Pain. Two of Pain's bodies then attacked the pair, but were confronted by Ibiki himself while Inoichi and his daughter fled to safety with Shizune.

Later, Inoichi and Shizune start to collaberate what they know about Pain and fiqure out that "Pain" is nothing more than Dead Puppets being controlled by someone close by. Suddenly, Human Realm Pain jumps down and probes Shizune's mind and figure out Naruto's location. Inoichi then looks on in horror along with his daughter as Shizune is then killed by having her soul ripped out.

After the Shinra Tensai Explosion, Inoichi and the other found Shikamaru and Shikaku after a moment of trying to trace Nagato, Inoichi discovers a way to find him.

Abilities
Inoichi, presumably being the head of his clan like his former teammates of their respective clans, has shown himself to be a highly capable ninja. He is well-versed in all of his clan's secret techniques. During the invasion in Part I, Inoichi skillfully performed the Mind Body Disturbance Technique to make the invaders he encounter fight themselves without any control.

Further proof of his skill is shown from his status as an interrogator during Pain's invasion of Konoha. He was able to skillfully probe a Rain ninja's mind even though Pain had guarded it with mental blocks and traps. He has also shown the ability to communicate telepathically with his daughter Ino.

Trivia

 * He is the only member of the Previous Ino-Shika-Cho trio whose wife has not been seen, though she is the owner of the flower shop Ino is seen working at.