Pacha is the leader of a village in Emperor Kuzco's unnamed kingdom. His hut is located at the very top of the village's hills where the sun hits perfectly. He resides there with his wife Chicha and his children, Chaca, Tipo, and Yupi. Pacha spends most of his time herding llamas and being with his family, which implies that his political responsibilities as village leader were not too demanding and the villagers can overall look after themselves. However, his role as chieftain became greater when his village is targeted by Kuzco in order to level it for his "Kuzcotopia" summer palace, as all the people in Pacha's village would lose their homes, and as such Pacha needed somehow to convince Kuzco not to do this in order to spare the village.
When the movie went by Kingdom of the Sun, Pacha was drastically changed during the production process that completely revamped the story. Originally, he was to be a younger man that was meant to be voiced by Owen Wilson, that looked identical to Kuzco, resulting in a "Prince and the Pauper" storyline. When Yzma discovered the switch, he was forced into acting as a puppet ruler by her. In the ending, Kuzco and Pacha would work together to stop Yzma's plans to awaken the dark god Supai and restore the sun to its proper place. The original role to assist emperor-turned-llama Kuzco in getting back to the royal city was to be Mata, a female llama herder, and a potential love interest for the selfish teen (aspects of the character that would later be used in Malina in the TV series). The major overhaul of story made the film a buddy movie, with Pacha and Kuzco having to trust each other through the adventure.
Pacha is very lovable and caring. He takes his position as village leader very seriously and attempts to do what's right for his people. He can be best described as a family man, spending most of his time with them. Upon meeting Kuzco, Pacha felt he was a spoiled brat but learned to forget that in an attempt to change the emperor's attitude around.
In the first film, Pacha is summoned to the palace by Kuzco and is told that his house on the hill will be destroyed to make room for Kuzco's summer home, as Pacha claimed that singing can be heard when the sun rises on his hill. Distraught and horrified that the emperor could be so callous, he travels home to tell his wife (Chicha) and his two children (Chaca and Tipo) that they have to leave their ancestral home. However, before he can tell them, he discovers that Kuzco has been transformed into a llama and dropped in the back of his cart. The two set out to turn Kuzco back to a human by getting to Yzma's lab. After the adventure and the defeat of Yzma, Kuzco decides to let Pacha keep his hut and village, claiming to have visited the hill and heard no singing. Pacha then claimed that he heard singing on the hill next to his, leading to Kuzco building a summer hut right next door to Pacha's. Pacha and his family welcome Kuzco into their lives and enjoy themselves in Kuzco's pool.
In the second film, Pacha is Kronk's friend. He disguises himself as Pachita, Kronk's mother-in-law (they initially planned for him to pretend to be his wife, but Pacha's wife, Chicha did that instead).
In the TV series, he is like a father to Kuzco and lets him live with him. He always gives Kuzco advice to help him out of any situation. For example, when Kuzco was transformed into a rabbit, he told Kuzco to "Make the best of what you've got," which in this case was speed.
In Cart Wash, when Kuzco is transformed into an elephant and laments how he is going to wash carts, Pacha tells him that elephants wash themselves through their trunks and he could do the same with carts.
After Kuzco's graduation in Graduation Groove, Kuzco reveals during the credits that he had Pacha and his family move into the palace with him as he loved living with them and would miss them.
Pacha made cameo appearances as a guest in several episodes of House of Mouse.
In the documentary The Sweatbox, the animators revealed that Pacha is forty-five years old.
In the trailer spots for the film, in the scene where Pacha, after rescuing Kuzco from a pack of Jaguars, accidentally ties him and Kuzco to a branch, he expresses confidence that they can get themselves out of the situation, only to promptly say "...or not." just as the branch starts breaking off. However, in the actual film, Pacha shows absolutely no loss of confidence in getting themselves out, and instead during the branch breaking off, Kuzco only responds by saying "I hate you" in a deadpan manner.