The Gan Jin leader was the chief of the Gan Jin tribe. Like the remainder of his tribe, he upheld a strong rivalry with the Zhang people. Very neat and high-strung, his personality reflected the ideals of his tribe.
Several months before the end of the Hundred Year War, the Gan Jin leader hoped to cross the Great Divide with his tribe. A tribesman had "reserved" an expedition across the canyon with the canyon guide, but the Gan Jin's rival group, the Zhangs, appeared, also hoping to cross the massive valley. When the rest of the Gan Jins arrived, it was decided by AvatarAang that the two would cross the Great Divide together. The canyon guide did, however, order the groups to dispose of any food before beginning the journey.
Neither tribe heeded said warning, resulting in the canyon guide being attacked by a canyon crawler, who had been attracted by the scent of the food. The assault resulted in the loss of the guide's earthbending abilities due to broken limbs, thus trapping the feuding people in the Divide.
Throughout their time in the canyon, the two tribes' bickering, to Aang's dismay, did not relent, and eventually resulted in the Avatar having to separate the two. While separated, the Gan Jin leader told Katara his tribe's version of the story that sparked the feud - their tribal patriarch, Jin Wei, had an ancient sacred crystal orb stolen from him by Wei Jin of the Zhang tribe, turning Katara against their rivals.
The next morning, the tribes continued to argue, to which Aang declared once more that harsh words would not solve problems, but action would. As a result, both tribes' leaders began to duel, a struggle to which Aang quickly put an end. However, this exposed the smuggled food to both Aang and the canyon guide, causing Aang to lose his temper, though his stomach quickly got the best of him. The Gan Jin leader then worked with members of the Zhang tribe to escape the canyon, narrowly missing an attack from a pack of canyon crawlers.
After briefly complimenting each other's survival skills, the Zhang and Gan Jin leaders then decided to duel once more, when the two briefly mentioned Jin Wei and Wei Jin.
Aang then explained that Jin Wei and Wei Jin were actually eight-year-old twins at the time of the orb crisis and that they were simply playing a game, "Redemption". Jin Wei had the "sacred orb", which was only a ball used in playing the game, but lost control of it. Wei Jin then took the ball, attempting to run it to the other goal, the "gates" mentioned in the legend, but stepped out of bounds. As per the rules of the game, Wei Jin was placed in the penalty box, the "prison", not for twenty years, but for a mere two minutes. Seeing that their feud was sparked by more of a silly game, the tribe leaders finally agreed to end it and march together to Ba Sing Se - unbeknownst to either of them however, the story was later revealed to be a lie.
Like the rest of his tribe, the leader of the Gan Jin was something of a snob, very stuffy and neat and unable to bear the sight of messiness. Due to Wei Jin's alleged stealing of the Gan Jin tribe's sacred orb a hundred years ago, the leader harbored a deep-seated hatred toward the Zhangs, particularly its leader. However, after Aang lied to end their feud, both leaders were able to settle their differences and travel to Ba Sing Se together.
The Gan Jin leader proved to be a great swordsman, keeping a straight sword upon his back at all times. Despite his elderly age, he showed great skill with the blade, and a nimble fighting style, being able to attack and evade with relative ease.