Like all Bajorans of the 24th century, Bareil lived a life of conflict and suffering during the Cardassians' occupation of his world. After the occupation came to an end, he attempted to bring stability among the various factions on Bajor. As a Vedek, Bareil was held in high esteem by the deeply spiritual Bajoran people and he earned great favour among them. After the disappearance of Kai Opaka, Bareil became the top candidate to succeed her as the new Kai. He lost the election to Winn Adami, however, but he was not an ambitious man and accepted the outcome of the election as the will of the Prophets.
Bareil also maintained a romantic relationship with Kira Nerys of Deep Space 9 for almost two years.
In the third season episode "Life Support", Bareil was gravely injured following an accident aboard his transport bound for DS9. He was to assist Kai Winn in negotiating a peace treaty with the Cardassian Union, but a plasma explosion aboard the transport left him close to death. Dr. Bashir was able to bring him back from the brink of death, but needed to expose him to dangerous levels of neurogenic radiation in order to do so. Bashir told the vedek that he should be placed in stasis for an indefinite period of time, until a cure for the radiation damage could be developed. Bareil insisted that Bashir find another solution, so he could remain conscious to help Winn. Bareil believed it was the Prophets who spared him in the explosion so that he could ensure the success of the peace talks. Dr. Bashir, on the orders of Bareil, gave him an experimental drug that let him function for a few days. However, the drug did irreversible damage to the vedek's organs, eventually destroying part of his brain. At Kira's urging, Bashir replaced the damaged brain region with an artificial positronic implant, so that Bareil could continue to advise Winn. Soon after the peace treaty was signed, the remainder of Bareil's brain was destroyed. Kira and Bashir decided to allow him to die, rather than replace his entire brain with a machine.