Ty Lee was a cheerful and energetic girl who hailed from the Fire Nation. As the daughter of a nobleman, she attended the Royal Fire Academy for Girls with her friends, Princess Azula and Mai. Growing up, Ty Lee dealt with six sisters who shared identical appearances with her. This caused her to feel a loss of individuality and led her to have a longing to be a unique, recognizable person, and a desire for attention from other people. Because of this, after she matured, she ran away from her home and joined a Fire Nation circus, becoming a skilled acrobatic performer and gaining more personal attention.

Ty Lee was a formidable hand-to-hand combatant, often utilizing chi-blocking, a unique form of martial arts that targets pressure points located in the human body. By striking these, she was able to disrupt an individual's chi flow and temporarily paralyze them, thereby also preventing the victim from bending for some time. Mai and Ty Lee were recruited by Princess Azula to hunt down and capture Prince Zuko and Iroh, and later Avatar Aang and his friends.

Mai later betrayed Azula to save Zuko's life, and when the infuriated princess retaliated, Ty Lee defended Mai by paralyzing Azula, which led to her imprisonment. While in prison, she met the Kyoshi Warriors for a second time and befriended them. In return for teaching them how to chi-block, they allowed her to join their group. Upon their release at the end of the Hundred Year War, Ty Lee adopted their makeup and clothes, effectively becoming part of a matched set once again, though this time with the reassurance that she could become a unique individual again whenever she wanted, simply by removing her makeup and uniform.