Oonoki is incredibly proud, headstrong, and boastful old man, who even in his old age refused to retire. He gets easily irritated and can sharply rebuke the young, not acknowledging their authority until they prove otherwise by deed. At the same time his stubbornness hides a deep concern for the future: confronted with Gaara's wisdom and Naruto's fervor, he recalls what he was like before his heart hardened. In him coexist the cynicism of an old veteran and the awakened faith in the alliance of villages. Oonoki does not hold back in his expressions and is able to sarcastically mock even an enemy, as he did with Deidara, reminding him of his defeat by Sasuke. However, in battle he becomes an inspirational leader, urging his comrades not to surrender even before the most terrifying opponent. He deeply honors his teacher Mu, addressing him exclusively with a respectful suffix. Despite his outward sternness, Oonoki is capable of admitting mistakes: it was he who first proposed that the Shinobi Alliance unite against Akatsuki.