Sinestro was a member of the Green Lantern Corps and was good friends with fellow Lantern Abin Sur. Abin Sur introduced Sinestro to his sister, Arin, who he later married. Sinestro began to take over his homeworld, Korugar, against Arin’s wishes believing that only he knew what was best for Korugar. One day, a suicide child bomber attacked and caused the death of Arin. Sinestro mentored Hal Jordan while he trained to become a Green Lantern. When the Guardians discovered what Sinestro was doing on Korugar, he was dismissed from the Corps. Sinestro formed the Sinestro Corps to fight the Green Lantern Corps. After Blackest Night, a Green Lantern ring picked Sinestro to once again become a Green Lantern.
On Oa, the Guardians forced Sinestro to recite the Green Lantern oath and then let him free. They believed that Sinestro receiving a ring was a chance for his redemption and told him to protect his sector. Sinestro returned to Korugar and found his Sinestro Corps torturing the citizens. One of the Corps spotted him and Sinestro demanded to know why the Corps were disobeying his orders to protect the planet. When he saw Sinestro wearing a green ring, he attacked Sinestro for betraying the Corps and so Sinestro killed him and destroyed his yellow ring. Sinestro went to find Hal Jordan and was attacked by him and he easily subdued Hal with his ring. Sinestro used the ring to create a new ring for Hal, and Hal tried to blast Sinestro with it without any results. Sinestro explained that the ring only had power if Sinestro allowed it since he was the creator. Hal heard sirens and went to see what the problem was and stopped Hal from saving a woman from a collapsing bridge. Then to teach Hal a lesson he completely fixed the bridge and saved the woman with his ring. Suddenly, Sinestro was attacked by Gregor of the Sinestro Corps and so Sinestro killed him and then asked Hal to help him destroy the Corps and save Korugar. Hal agreed to help, but as he went to tell Carol Sinestro stopped him and wouldn’t allow him and so they flew off to Korugar. Sinestro told Hal that his plan was to stay hidden until sunset and then Sinestro would fight the Corps as Hal deactivated the Yellow Central Battery, since it can only be deactivated by a Green Lantern. Sinestro then showed Hal how to turn their uniforms to black and they hid in some ruins, waiting for sunset. They watched as the Corps were about to kill a Korugaran and were stopped by Arsona and Sinestro decided to intervene. Sinestro was captured by the Corps and they failed to remove his ring and so they put him in a cell full of Korugarans. Arsona was among them and was hostile towards Sinestro, who tried to explain that he was only ever trying to protect Korugar. Hal was in the cell next to Sinestro and Hal suggested that Sinestro create rings for the Korugans so that they could fight the Corpsmen, even if they only lasted for a few minutes. Sinestro succeeded but was then attacked by the Korugans, but the rings didn’t work against him. Sinestro was able to command his Green Lantern to destroy the cells and after Hal recharged his ring they all began to fight the Corps. Hal and Sinestro returned to the Central Battery and Sinestro explained that the first time must not have worked since Hal was using Sinestro’s lantern and a ring created by Sinestro. Sinestro then used his lantern to extinguish the Central Battery, causing it to retract the energy from the Corps’ rings and also making them go into a coma. The Korugans then told Sinestro that he wouldn’t be welcomed back to Korugar and that if he returned he would be considered an enemy. Sinestro sent Hal home with only enough energy to get back to Earth.
Sinestro went to Ogoro and confronted Starstorm, telling him that he needed his help finding Lyssa Drake. Sinestro forced Starstorm to wear his helmet and locate Lyssa. Lyssa attacked and tried to absorb them into the Book of the Black. Sinestro tore a page from the book and saw a possible future where the Guardians killed off the Lanterns and starting a third army with the first Lantern, Sinestro being a part of the Indigo Tribe, Hal dying, Ganthet obtaining a White Power Ring, and his own death. Lyssa continued to torture Starstorm, trying to get him to kill himself as Sinestro removed Starstorm's helmet and threw it at Lyssa, causing an explosion. Sinestro decided to leave Lyssa alive, deciding she may still have use to him and then left.
Revenge of the Black Hand
Sinestro went to Earth and returned power to Hal's ring, telling him he still had use for Hal. Hal refused to help Sinestro and after Sinestro threatened Carol, he punched Sinestro. Sinestro restrained Hal and told him the Guardians were going to replace the Green Lantern Corps. Suddenly, the Indigo Tribe arrived and Indigo-1 explained that they felt the Guardians were wrong to let Sinestro keep a ring and so they had come for him and then teleported away with both Sinestro and Hal. Sinestro was shackled and a tribesman began cleansing Sinestro of the green energy until Sinestro broke free and attacked him. However, the Indigo tribe subdued him and continued the process, making him a member of the tribe and he went with the rest of the tribe to confront Hal. Hal reminded them of the alliance between the Green Lanterns and Indigo Tribe, and Indigo-1 replied that the alliance stood and that they would transport Hal back to Earth. Hal refused to return without Sinestro and escaped into the Forbidden Jungles in search of their Central Battery. The Central Battery was destroyed and the rings lost their power, leaving Sinestro freed along with other criminals that were being controlled by the rings. Hal saved Sinestro and as they ran into the jungle he explained that the Indigo Tribe members were all brainwashed criminals. They escaped in a jeep construct and then found Nastramo and Sinestro tried to threaten him into fixing the Central Battery. Hal convinced Sinestro to do things his way and Sinestro went to hold off the criminals while Hal and Nastramo returned to the Central Battery. Nastramo succeeded in repairing the Battery and this restored the Indigo Tribe, including Sinestro. Hal asked the Tribe to release Sinestro, since he needed him, and Indigo-1 agreed on the condition that Hal would help him find redemption without the ring.
The Indigo Tribe released Sinestro under Hal’s custody and Nastramo inverted the bond between Hal and Sinestro’s rings so that Hal controlled Sinestro’s ring. Sinestro asked about the Black Hand and when they went to the place he was last seen, they found black slime that indicated the Black Hand commited suicide to avoid his Indigo ring. Indigo-1 teleported Hal and Sinestro to Korugar and Sinestro took Hal to his secret base and opened a vault that contained the Book of the Black. Sinestro opened the book to find out more about the Guardians and they were then teleported to the Black Hand’s home. The Black Hand took the book and was enraged when he saw that it read “Hal Jordan is not your enemy” and then attacked Hal and Sinestro. Hal shot Black Hand in the head to buy them some time and tried to contact Carol, since they needed two rings of different colors to defeat him. Black Hand returned and sent hordes of zombies against Hal and Sinestro. Sinestro summoned his Yellow Lantern and then he and Sinestro used their rings to destroy the Battery and destroy the undead.
Sinestro was buried alive by Black Hand and later he woke up and dug himself out after hearing Hal trying to dig him out and attacked Black Hand with a shovel. Hal and Sinestro touched their rings together and used the spark of will to summon Hal’s lantern and recharged their rings. However, the Guardians showed up and with the First Lantern, they made Black Hand suck Hal and Sinestro into a vortex. This caused their rings to malfunction and believe Hal and Sinestro were dead and then merge back into one ring. Hal left one last message for Carol as they were sucked into the vortex.