Byakuya Kuchiki is the 28th head of the noble Kuchiki clan, one of the four great noble families in Soul Society. As such, Byakuya acts in an aristocratic manner — he seems always serene and apathetic towards other people, even when he is actually deeply conflicted. He is also extremely calm, even in battle, and is very seldom surprised by even the most drastic of actions. Ironically, when he was younger, he was quick to anger and very hotheaded, as noted by his grandfather, Ginrei Kuchiki; similar to the way Ichigo and Renji are now.
Byakuya strongly believes in law and order. As the head of one of the great noble families and as a captain in the Gotei 13, he always works hard for a peaceful society. He thinks that if someone in his position doesn't follow the rules as a good example, then no one will follow them. He believes that to maintain the order, all law-breakers must be punished, even if that goes against his own wishes. Despite his icy and regal manner, Byakuya cares for and protects those important to him, even referring to Rukia as his "pride".
Byakuya is popular among the female Soul Reapers of Soul Society, and was voted number one in the "captain we desire to release a photo book for" poll taken by the Soul Reaper Women's Association. He likes cherry blossoms, night time walks, and spicy food.
Byakuya wears the standard captain uniform along with a white headpiece called a kenseikan (symbolizing his noble rank as the head of the Kuchiki family) and a white scarf made by the master weaver, Tsujishirō Kuroemon III. The scarf is made from silver-white windflower light silk (ginpaku kazahana no uzuginu) and is a family heirloom handed down through the generations to the head of the Kuchiki family. Ten houses can be built for the cost of just one such scarf. In the anime, the scarf is an extremely light green (episodes 52 and 53).
Byakuya seems to have a comic side to himself despite his extremely serious personality. He not only attends the lieutenants' meeting when Renji Abarai is absent, but also implies that he attends the meetings of the Soul Reaper Women's Association when Rukia is absent. In the Soul Reaper's Illustrated Picture Book in episode 118, he remarks"part of a captain's responsibilities are to make sure the lieutenant's responsibilities are taken care of." When Renji asks him if he also goes to Rukia's meetings, Byakuya responds only by smiling. In the Soul Reaper's Illustrated Picture Book in episode 113, Byakuya jokingly remarks that he uses Senbonzakura to cut his hair. In one of the omake chapters, Byakuya claims that life in general is not supposed to be entertaining, and even makes up an idea for a game that is not meant to be amusing. It was also shown in an omake chapter that Byakuya's artistic talent is similar to Rukia's (that is, non-existent). However, Rukia sees it as better than hers.