Hundun started out as a member of the Anvil of Heaven at Chorh-Gom Prison and was among the Anvil of Heaven members that tried to prevent Tai Lung from escaping Chorh-Gom Prison. When Po had defeated Tai Lung, Chorh-Gom Prison was closed down leaving Hundun without a job. He lost his home and his wife leading Hundun to pin the blame of this on the Dragon Warrior. When he arrived in the Valley of Peace, he unknowingly befriended Po and learned some Kung Fu moves from him. When he finally learned that Po was the Dragon Warrior, he ended up attacking Po after easily taking down the Furious Five (Po unknowingly told Hundun of their weaknesses). Po manages to fight Hundun in front of everyone and managed to defeat Hundun when the Statue of Po fell on him. Hundun was returned to Chorh-Gom Prison as a prisoner as Hundun vows to have his revenge on Po.
In "Challenge Day," Hundun returns having replaced his broken horn with one that was filled with knock-out arrows. He takes the opportunity to take part in the Dragon Warrior Challenge where he manages to defeat Po (who was still weakened from rescuing a child from a collapsing chimney). After using knock-out arrows on Shifu (who stated that he made up the Dragon Warrior Challenge), Hundun ended up going on a rampage in the village until Po recovered and defeated Hundun.