Iruka is a man of average height and build. He has black hair (brown in the anime) that he keeps in a ponytail, dark eyes and a scar that runs across the bridge of his nose — which he has had since his youth. He wears the standard Konoha shinobi outfit complete with forehead protector, sandals, and flak jacket. His sleeves are also rolled up.
Iruka is usually quite serious, especially about his job and is strict in teaching his genin students. He relates to Naruto, growing up as an orphan and trying to be playful and silly for people to recognise him. Secretly, after his parents were taken by the nine-tailed fox, he has experienced unbearable loneliness. He socialises with others, albeit colleagues, and takes Naruto out for ramen meaning he does live a different life outside his job.
Iruka is one of the teachers at Konohakugaru's Ninja Academy. He trained Rock Lee, Neji, Tenten, and many other shinobi of Konohagakure. He is first seen teaching three new genins who abhor hardwork which opposes Rock Lee's 'dream'. Rogue ninjas target the genin and Iruka appears at the scene.