Teo's home village was destroyed by a flood when he was still an infant. The natural disaster cost his mother her life and rendered him paraplegic (paralyzed from the waist down). Under the leadership of his father, the surviving villagers set out to search for a new home and stumbled upon the deserted Northern Air Temple, about ninety years after the Air NomadGenocide. The mechanist created a glider for his son, a concept based on the Air Nomad gliders he had found in the temple. Due to this, Teo, otherwise bound to his wheelchair, was granted a new life in the sky, where his aerial acrobatics were the envy of all the other glider kids.
After hearing a story about the "air walkers", Aang, Katara, and Sokka traveled to the Northern Air Temple in the hope of finding surviving Air Nomads. To his dismay, Aang noticed that the air walkers were merely gliding instead of airbending, commenting that they had no spirit. The statement was immediately contradicted by Teo, who flew closely overhead, laughing loudly and silently challenging Aang to fly with him. Under the encouragements of many spectators, the two children engaged in an aerial acrobatics contest, showing off their skill with loops and spins. To counter Aang's air scooter move along the side of the temple wall, Teo used a cylinder strapped to the back of his wheelchair to create a sky picture, depicting a sour-looking Aang, ending their bragging contest. Although disgruntled at first, Aang eventually remarked that even though Teo was not a born airbender, he definitely had the spirit of one.
Teo proudly toured the three friends around the temple to show them the many alterations his father made to the ancient settlement. After Aang openly showed his disapproval on the many "upgrades", Teo took Aang and Katara to an unblemished part of the temple, the hallway leading up to the Northern Air Temple sanctuary. On the way, he pointed out to the young airbender that even though the temple might be different, the creatures living there, like the hermit crabs, were likely direct descendants of the ones living there during the time of the Air Nomads. This prodded Aang to later realize that even though Teo and the other Earth Kingdom refugees were not born there, they had "found this empty shell and made it [their] home", drawing a comparison with the native hermit crabs. Aang eventually opened the airbending powered door to the sanctuary so they could explore inside. However, instead of finding secret Air Nomad relics, they found a secret storage room of the mechanist where he produced weaponry for the Fire Nation.
Resenting the thought that the mechanist aided the Fire Nation with his inventions, Teo and Aang confronted him, forcing him to break his arrangement with War MinisterQin. In retaliation, the Fire Nation launched an attack on the temple. In order to defend his new home, Teo, along with Aang, led the other gliders in an air-borne assault, dropping a wide variety of bombs on the troopers. They were eventually successful in driving away the advancing soldiers.
Months later, Teo was part of the "ragtag team of friends and allies" which Sokka had summoned to take part in the modified invasion plan. Before the start of the Invasion of the Fire Nation, Teo offered Aang a new glider, which he had made with his father. During the invasion, Teo piloted one of the earthbending-powered tanks into battle. After the destruction of the submarines in which they had arrived, the warriors realized the invasion had failed and decided to surrender. The adults were to remain behind while the youngest, namely Aang, Katara, Sokka, Toph, Teo, The Duke, and Haru, escaped on Appa. Due to this, Teo and his father had to part ways. He hugged his father goodbye, telling him that he was really proud of him. The escapees traveled to the Western Air Temple.
Struck by how different the Western Air Temple was from its northern counterpart, Teo quickly befriended The Duke and Haru, with whom he thoroughly explored the temple in search of secrets room, challenging "Duke" to a race. During one of these exploring expeditions, Teo rode down the Hall of Statues and injured himself due to malfunctioning brakes which he fixed later on.
Teo remained with the group until PrincessAzula attacked the Western Air Temple. During the assault, Toph and Haru created an earth tunnel through which the party was able to escape. Due to Appa's reluctance to enter the tunnel, Teo, Haru, The Duke, Hakoda, and Chit Sang parted from Team Avatar. While the latter escaped on Appa, facing Azula and her airships head on, Teo and the others escaped through the back, where a stolen airship was at their disposal for a safe getaway.
At Zuko's coronation as the new Fire Lord, Teo was present and reunited with his father. He applauded and cheered as Zuko declared the Hundred Year War to be over.
Teo was kind and spirited; he loved nothing more than the freedom of flying his glider. He did enjoy showing off on occasion, and even tried to out-fly Aang when they first met, creating a picture out of smoke in the sky of Aang frowning. He was respectful of others, honest, and did not let his handicap get him down. Teo respected his father and understood why he acted as he did, though he was highly disappointed and angry when he learned that the mechanist had been making weapons for the Fire Nation.
Although Teo has not shown any physical fighting skills, he proved to be a very capable flyer, able to keep up with Aang in speed while performing several loops. He was capable of corkscrewing through the air while flying as well. Teo's skills were developed enough that he even demonstrated the ability of making images in the air. Despite his paralysis, Teo could operate his glider at relatively high speeds.
Teo has displayed some form of combat skills he had was with his glider, being able to accurately throw bombs while flying. Besides his glider, Teo has shown the ability to operate machinery, seeing how he operated an earthbending-powered tank before the eclipse.
Teo is also seen in the first Super Deformed Short, School Time Shipping, aiding Aang in his pursuit to ask Katara to the dance both more extravagantly and earlier than the other three suitors; Jet, Haru, and Zuko. Aang stood on the back of his glider to shape words in the air, while Teo whizzed around.