Isshin Kurosaki, formerly known as Isshin Shiba , is the former captain of the 10th Division, father of Ichigo Kurosaki, Karin Kurosaki, and Yuzu Kurosaki, head of the Kurosaki family, and formerly that of the Shiba Clan.
Isshin is a tall, muscular man with spiky black hair and brown eyes. He has thin facial hair around his mouth and on his cheeks. As a doctor, Isshin usually wears a white lab coat over his otherwise more casual shirt and trousers. He has the appearance of a man in forties, as noted by his daughter, Karin.
As a Shinigami, he wears the standard Shinigami Shihakushō, along with a tattered captain's haori, worn like a sash and fastened over his left shoulder. The Division insignia cannot be seen as the haori is worn presently.
When he was the captain of the 10th Division, Isshin wore the typical Shinigami uniform, with a sleeveless captain's haori. He had noticeable sideburns, did not have facial hair at the time, and had slightly shorter hair.
Isshin typically acts in a goofy, energetic, and fun-loving manner. Loud voice, big smile and a wide range of facial expressions are his trademark features. He's prone to attack his son all of a sudden for every reason, from being late for a dinner to simply waking him up. Like he claims, it was all to make Ichigo stronger, which actually paid off. Sometimes Isshin can be the life and the soul of the party as shown during the festival in Karakura Town. Initially starting the fun with his daughters he finally took almost all of Ichigo's friends with him.
During his time in Gotei 13 Isshin was a lazy and carefree captain who often tried to make his subordinates do his work for him. For this reason he was in bad terms with Rangiku Matsumoto who was often forced to call him back to order. Isshin was delighted seeing how diligent Tōshirō Hitsugaya was doing all the paperwork and, on the spur of the moment, saw the future of his division in him.
Isshin has also a perverted and lecherous side. He loved commenting how Rangiku's boobs were shining from sweat and bullying Ichigo that his sisters, who were piggybacked by him, weren't wearing underwear. However, when he encountered naked Masaki, he blushed and demanded her to not act casually while looking like that.