Kyle Reese (portrayed by Michael Biehn) is a soldier in the Human Resistance in the Terminator franchise. Recruited after being liberated from a Skynet concentration camp, Kyle quickly learned the best ways to combat the machines. When SkyNet sent a Terminator back in time to kill Sarah Connor, Kyle volunteered to be sent back to protect her. John Connor's made their final assault on Skynet's main lab complex in 2029 and captured the Time Displacement Equipment, using it to send Kyle back in time to 1984.
When Kyle arrived in 1984, he arrived naked since the time displacement field would only transport a living organism, not dead matter. He came across a homeless man in a Los Angeles alleyway and took his trousers, then as he evaded the police he acquired a shirt and coat. He would later steal a pistol and shotgun from a police cruiser as he began his search for Sarah Connor. Twenty-four hours later, he would find Sarah inside the Tech Noir nightclub, about to be executed by the T-800 sent to kill her. He fired on the cyborg and briefly disabled it and took Sarah with him, later explaining who he was and why Sarah was being hunted. Of course, Sarah didn't believe him at first, thinking that Kyle was insane. Even the criminal psychologist Dr. Silberman thought as much after questioning Kyle when he and Sarah were brought in by the police.
Kyle was briefly detained by the LAPD until the Terminator attacked the police station, murdering every officer that stood between it and Sarah, its target. In the chaos, Kyle and Sarah made their escape and went into hiding just beyond the city limits. While hiding, Kyle explained to Sarah where he was from and what life was like in the future. He and Sarah later took shelter at a motel where Kyle revealed his true feelings for Sarah, which stemmed back to when John gave him an old photograph of her. The two acknowledged their feelings for each other and made love.
Kyle and Sarah were forced to flee from the motel when the Terminator tracked them down. As they fled across the highway, Kyle tried to blow up the Terminator's bike with several pipe bombs, but would suffer gunshot wounds to his arm. The van that he had stolen would later be crushed by an oil tanker that the T-800 hijacked after losing its bike. Forced to flee on foot, Kyle and Sarah were briefly seperated and Kyle managed to stuff a pipe bomb into the feed pipe of the tanker as it passed him to attack Sarah. The pipe bomb exploded and destroyed the tanker, with the Terminator apparently being consumed in the blast. Kyle had taken cover in a dumpster as the truck exploded, but was still tired and injured after the ordeal. He and Sarah embraced, believing their longest night was finally over, but the Terminator wasn't finished yet.
The Terminator, no longer covered by clothing and flesh, rose from the wreckage of the tanker. It continued to pursue Sarah and Kyle, dragging its damaged leg which slowed its progress. Kyle and Sarah took cover in a computer factory, but an exhausted Kyle was struggling to keep going. With encouragement from Sarah, he found the strength to keep moving and fought against the Terminator as it followed them up a catwalk. Kyle beat the android across the head with a metal pipe, but to no avail. The robot knocked Kyle to the floor, who then pulled one last pipe bomb from his coat and slipped it into the T-800's abdominal cavity. When the bomb exploded, the Terminator's lower body was blown to scrap. Kyle, however, was struck by a piece of shrapnel and killed.
The future is not set...
Kyle Reese's future is drastically changed over the course of Terminator: Genisys. In this film, Kyle (played by Jai Courtney) is sent back in time on his original mission to protect Sarah Connor, but as he time-jumps he witnesses John being attacked by one of his own soldiers. He is unable to do anything about it as he suddenly finds himself in 1984, but shortly after his arrival he is attacked by a T-1000, a shape-shifting Skynet android. His life is saved by none other than Sarah herself who is accompanied by the Guardian, a reprogrammed T-800 that has spent years protecting Sarah and shows visible signs of ageing.
After helping Sarah and the Guardian destroy the T-1000 and the T-800 originally sent to kill Sarah, Kyle decided to help them try and destroy Skynet before it was ever created. Sarah and Guardian had developed a crude Time Displacement Device that would take them forward to 1997 when Skynet was supposed to come online, but Kyle recalled a vision he experienced when he first entered the timestream, a memory of a life he hadn't lived with his childhood self telling him an important date in 2017. Kyle tells Sarah about this memory and Guardian confirms that it could be the result of the timeline being fractured. The trio revise their plan and set the time machine for 2017. Kyle and Sarah leave without Guardian whose flesh covering was damaged, preventing him from travelling through the displacement field and forcing him to simply wait until Kyle and Sarah reappeared in 2017.
When Sarah and Kyle arrived in 2017, the Guardian was not able to intercept them as they materialized above him on top of an overpass in the middle of traffic. Both of them were arrested and while in custody, they learned about an app called "Genisys", which Kyle remembered from his alternate memories that "Genisys" was a new form of Skynet. John Connor arrived the hospital and helped them escape. It seems that John traveled back in time right after Kyle did. It is during this time that John accidentally revealed that Kyle is his father.
Pops showed up and shot John, revealing that John had been transformed into a T-3000 Terminator by Skynet. Sarah, Kyle, and Pops managed to escape John with Sarah noting that John Connor is no longer humanity's last hope, but Skynet's last hope. The trio went to a safe house to collect weapons in order to destroy Genisys. While stocking up, Kyle confronted Sarah about the fact that she lied to him about John's parentage. She told him that John was the one who really manipulated him as John did so to ensure his own existence. Kyle admitted to being in love with Sarah, but she pushed him away because she said that she was afraid that he would die like in the previous timeline.
John tracked them to their safe house and they proceeded to run from him using a stolen school bus. John attempted to kill them, but they survived and were arrested again. This time, they were helped by Detective O'Brien, who remember them from 1984 as he was saved by Kyle and Sarah. On the way out, they ran into the young Kyle Reese, who was afraid of all the gunshots. Sarah told him to run and not look back. After a helicopter chase with John, they went to the Cyberdyne building, where Genisys was being created. John came for them and almost killed them, but Pops slowed him down by trapping both of them in an electromagnetic field created by the prototype Time Displacement Equipment. While the two was struggling, Sarah and Kyle rigged the building with explosives. At the last minute, Pops was thrown into a pool of mimetic polyalloy before John was killed by the electromagnetic field. Sarah and Kyle managed to find shelter in a bunker right as the building explodes. Trapped in the bunker, Sarah and Kyle believed they are about to die due to the lack of air, but they were saved by Pops, who had just been repaired and upgraded by the mimetic polyalloy.
The trio went to the home of the young Kyle Reese, making sure he knew that Genisys is Skynet. This completed the loop for the adult Kyle's memories. Sarah mentioned that she could now choose the life she wanted before she and Kyle shared a kiss, indicating that she still chose to be with him. Sarah, Kyle, and Pops then drove off.