Following Chit Sang's detainment in the cooler for firebending, the Warden came to him and warned him not to try to escape, stating that he would "sooner jump in the boiling lake himself than let that record fall".
Later, when the prison discovered that Zuko disguised himself as a guard, the Warden came to visit him, instantly recognizing him. When Zuko asked him how he knew who he was, the Warden revealed that he was Mai's uncle. Then, he told Zuko to behave, as if he did not, and "the other prisoners found out who he was, the traitor prince who let his nation down, they'd tear him to shreds". Zuko then asked why he did not just tell the Fire Lord, Ozai, and collect a reward, to which the Warden stated that he intended to eventually turn Zuko in.
Later, he discovered Chit Sang's escape attempt when he screamed after being burned by the boiling lake. He ordered the escapees be recaptured and placed in coolers, and that the entire prison be placed on lock-down, due to the fact that there were new prisoners arriving.
Later, the Warden greeted the new prisoners. In his usual arrogant fashion, he told them that their time in the Boiling Rock did not have to be unpleasant, so long as they behave. He stopped at Hakoda, who refused to look him in the eyes, and ordered him to do so. After being tripped by the Southern Water Tribechief, he ordered the prisoners into their cells.
Afterwards, he went to interrogate Chit Sang about the escape attempt. After asking whether the prisoner was comfortable, to which Chit Sang answered yes, the Warden kicked Chit Sang over. Chit Sang angrily declared that he would not talk, unwittingly revealing that there was another conspirator. The Warden proceeded to have Chit Sang tortured, by being held upside down until the blood rushed to his head, until he talked. Eventually, the prisoner succumbed to the torture and revealed that it was a man disguised as a guard who came up with the plan.
He then made Chit Sang pick the impostor out of a line up, unknowing that he picked the wrong one. He proceeded to interrogate that guard until he was interrupted by PrincessAzula, who told him that the guard he was interrogating was not the mastermind behind the escape plan. He asked her how she knew, to which she simply replied that she was a "people-person".
Much to his dismay, the Warden arrived at the prison yard to see that not only were the prisoners out despite his earlier lock-down order, but also that a riot was ongoing. He left to take control of the situation, but was captured by Suki while she, Sokka, Hakoda, Chit Sang and Zuko were escaping. The five of them used the Warden as a hostage to get onto the gondola.
While the gondola was running, with Zuko, Sokka, and Suki battling Azula and Ty Lee, the Warden managed to break free from his restraints and yelled for the other guards to cut the line, preferring to die than have his record broken. Chit Sang and Hakoda managed to restrain him, but not before the damage was done and the guards began cutting the line. However, Mai intervened and saved Zuko and the others from falling to their deaths. The gondola managed to get to the other side of the lake, and Hakoda told the Warden that his record was officially broken.
After Ozai was overthrown and the Hundred Year War ended, the Warden somehow managed to earn his niece and Ty Lee their freedom, which showed that even after Mai assisted in the escape that ruined his record at the prison, he still cared for his niece.
The Warden, who was the highest official of the Boiling Rock prison, was very demanding and impatient, yet was skilled at what he did. He was particularly proud of the no escape record of the Boiling Rock, a record he would die to keep. He was very bossy and demeaning when he talked to prisoners and guards, with the obvious exception of Princess Azula, who was in a higher position than him. He only treated prisoners well on a few occasions, but mostly in condescending ways. Despite his obvious lack of kindness, he may have had a softer side as Mai said that he managed to pull some strings to get her out of prison, despite the fact she helped Zuko, Sokka, and the others escape the Boiling Rock and shatter the Warden's otherwise perfect record of inescapability. He did also seem to have cared for his family, as he was angry that Zuko broke up with Mai.
The Warden was voiced by American actor Wade Williams, who has a starring role as Captain Brad Bellick on Fox's television series Prison Break, about a man jailed for a crime he did not commit, who then tries to escape from prison.
During the previews at the New York Comic-Con in 2008, it was revealed that his design is based on one of the show's staff members, Oh Seung-hyun.