Before being exposed to the horrors of the post-nuclear future, Sarah (portrayed by Linda Hamilton) was an average single woman living in Los Angeles trying to get by as a waitress. That all changed on the night she met Kyle Reese and was pursued by a cyborg assassin known as the Terminator, which sought to kill her and thus prevent the birth of the man that would destroy the machines in the future. During those two nights in 1984, Sarah and Kyle ensured the birth of John Connor by conceiving him together as they hid from the relentless Terminator. The pair managed to destroy the killing machine, but Kyle was killed doing so, leaving Sarah to raise John alone.
Terminator 2: Judgment Day
In T2, which is set eleven years after the first film, Sarah Connor (once again portrayed by Linda Hamilton) is locked up within Pescadero Psychiatric Hospital, having been deemed insane due to her fantastic tales of the coming nuclear event of Judgment Day and training her young son John in the art of warfare to prepare him for the war against Skynet. During her confinement, Sarah keeps herself physically and mentally active as she makes several attempts to escape and find her son, who was put into foster care. One night she almost achieves escape but is restrained by several orderlies. However, she is rescued by a figure from her nightmares: another Terminator - identical in appearance to the cyborg that hunted her years before - that was reprogrammed by John Connor's future self and sent back in time to protect his younger self. Sarah is liberated from Pescadero by the Terminator and John, the three of them working together to elude the T-1000 android sent back to kill John, and to prevent Judgment Day by stopping Skynet's creation. Their struggle appears to be over following their bombing of the CyberDyne building and the destruction of both the T-1000 and T-800 at a steel mill.
Terminator 3: Rise of the Machines
Sarah Connor makes no appearance in the third film, having apparently died of leukemia several years previously. She was diagnosed in 1994 and only given six months life expectancy, but she managed to fight the disease for three years. Sarah Connor died on August 29th 1997, the original date that Judgment Day was meant to occur. Even though the bombs didn't fall, Sarah wasn't convinced that the struggle against Skynet was over, and after her death she was secretly cremated and her ashes scattered. In accordance with her will, her coffin was filled with several weapons for her son and his next guardian to wield in the coming battle.
In the fifth Terminator film, the timeline has been radically altered. Events have changed due to interference from forces originating from a divergent timeline and Sarah Connor (this time portrayed by Emilia Clarke) is thrust into the conflict between man and machine much sooner than in the previous timeline. In 1973, Sarah's parents were murdered when a T-1000 android was sent back by Skynet to prevent John Connor's birth. Sarah's life was saved by a T-800 referred to as the "Guardian", sent back to protect her by persons unknown. Since that fateful day, Sarah has been trained by Guardian (whom she calls "Pops") to prepare her for other possible attacks from Skynet assassins and to find a means of changing the future by preventing Skynet's creation.