Billions of years ago, Maltusian scientist Krona created the power gauntlet to harness the Green Energy of Willpower. He later used it to aid in his escape from the Manhunters, which his fellow Guardians sent to apprehend him after he was charged with heresy for attempting to see the beginning of the universe. His attack on them altered their programming, leading to the Massacre of Sector 666.
After the Guardians captured him, they brought the gauntlet into the Foundry where they studied it, and used it's technology to develop the Green Lantern Power Rings. The gauntlet itself was kept under guard at all times.
War of the Green Lanterns
During this event, while using the tunnels under Oa's surface to get to the Central Power Battery to re-purify it from Parallax, Hal Jordan, John Stewart, Guy Gardner and Kyle Rayner stumble upon the room where the Gauntlet is being held. After a brief fight with Shedd, who was assigned to guard it, Guy is allowed to take it.
Later, Guy uses it in an attempt to fight off the Guardians, who were possessed by the Entities. He is immediately shocked to unconsciousness by them, and Krona takes it from him.
Rise of the Third Army
Near the end of this event, Guy Gardner, who had been set up and expelled from the Green Lantern Corps by the Guardians, enters the Foundry to retrieve his ring. It becomes apparent that this is not possible, so he takes the Power Gauntlet instead. He uses it to distract the Guardians long enough for Kilowog to disable the trap they had set for the Green Lantern Corps. One of the Guardians quickly takes it from him.
Later on, several major events occurred that turned the universe against the Green Lantern Corps. In an attempt to help the Corps be able to do their jobs again without being hated and feared, Hal Jordan, who was the leader of the Corps at the time, decided to turn himself into a scapegoat. He stole the Power Gauntlet from the vault it was being kept in on Mogo, and fought Kilowog with it to make it look more realistic. He left the Mogo and the Corps behind, despite their efforts to stop him.
Currently, with the Corps gone, Hal is using the Gauntlet to protect the universe.