Kyoshi was the Earth Kingdom-born Avatar immediately succeeding Avatar Kuruk of the Northern Water Tribe, and preceding Avatar Roku of the Fire Nation. She died at the age of 230, making her the oldest known human. Kyoshi was a tall woman, possessing the largest feet of any Avatar. Her traditional weapons were golden metal fans which, in addition to her manner of dress and style of fighting, were adopted by the Kyoshi Warriors of Kyoshi Island, her homeland.

Unlike her successors, Roku and Aang, Kyoshi was determined that only true justice could bring peace, and had no qualms about killing enemies to achieve this goal. Employing these methods, she was a generally effective Avatar. However, some of her actions also caused long-term problems for the Earth Kingdom; while ushering the world into a 233-year-long era of peace, the death of Chin the Conqueror and her foundation of the Dai Li would lead to the decline, corruption, and fall of her home country. Because of this, Kyoshi later came to deeply regret the creation of the Dai Li.