Ikkaku is bald, a fact that is made fun of by many. The 11th Division lieutenant, Yachiru Kusajishi, calls him either "cue-ball" or "pachinko head", a result of her fondness for giving people nicknames or when he questions her direction skills. As a result of the constant ridicule he gets, Ikkaku is very self-conscious about his baldness, to the point where he will threaten anyone that points it out. Ikkaku's bald scalp is reflective, which causes members of the 8th and 11th Divisions to mistake it as a full moon in one of the anime's omake segments, much to Ikkaku's annoyance. He also has distinctive small red markings near his eyes. Unlike most Shinigami, he does not wear tabi with his sandals.

In terms of attitude, Ikkaku is a stereotypical 11th Division member — violent, fight-loving, and rude; this has been noted by Tetsuzaemon Iba, among others. He loves fighting so much that he is unwilling to travel anywhere without a sword, resorting to carrying a wooden one when posing as a student at Ichigo's school. He does have a sense of loyalty and responsibility, however, unlike many of the lower-ranked 11th Division members. Ikkaku is fiercely loyal to Kenpachi, under whose command he wants to fight and eventually die.

Ikkaku has many personality traits in common with his division's captain Kenpachi Zaraki, which is why they seem to have so much respect for one another. Ikkaku considers fighting fun and tries to get as much "fun" as he can out of his opponents, so much so that he will take deadly risks to drag out the fight for as long as possible. During a fight with a challenging opponent, he is almost constantly smiling, much like Kenpachi does. Like all 11th Division members, he considers the only honorable battles to be those fought one-on-one and even the threat of death is not a reason to ignore this fact, since, as a rule, the winner is only determined when the other is dead. He does consider surviving an otherwise lost battle good luck, however, he's also sensible enough to carry a blood-clotting ointment in the hilt of his Zanpakutō.