Sarah Connor's transformation from a mild-mannered waitress with a weird pet iguana to the ultimate survivalist bad*ss who's just mildly insane transpires over the course of her first two on-screen appearances, in James Cameron's original The Terminator and its sequel, Terminator 2: Judgment Day. Her core human vulnerability is what makes her such an indispensable character and one of the best action heroes in movie history. Sarah (Linda Hamilton) is barely scraping by as an LA waitress during the events of the original movie. She's a sweet, unassuming woman who quickly finds herself in danger, as a mysterious killer is systematically slaughtering every Sarah Connor in the phone book. Luckily for Sarah, she is the third such listing, and is on high alert when the handsome killer approaches her at a downtown club, Tech Noir, clutching a .45 longslide with a laser sighting and wearing a fashionable jacket. That's when her adventure really gets weird - the killer is blasted with a shotgun by a different handsome-yet-dangerous man in a fashionable jacket, who convinces her to tail him if she wants to live. This is Kyle Reese (Michael Biehn), who explains that her would-be assailant is actually a Terminator (Arnold Schwarzenegger), a lethal cyborg sent back from the future by a machine-led military force hellbent on eradicating humanity. Kyle, too, has been sent from the future, but his mission runs counter to the T-800's: He is a soldier, sent back in time to protect Sarah, to ensure she lives to give birth to her eventual son John, who will lead our species to survival against a robot apocalypse. What John may not have told Kyle, however, is that he is actually John's father, doomed to die protecting Sarah - but not before falling in love with her and conceiving John. Throughout the course of the first film, Sarah learns how to fight and fend for herself while fleeing the first Terminator with Kyle.
By the the events of the second movie, which takes place around 1995, Sarah has undergone a total transformation of mind, body, and soul. Hamilton wanted to ensure that the character looked like she had toughened up after her experiences in the first movie, and thus began an extensive training regimen to prep for the sequel. She began working out six days a week for three hours a day to get into peak athletic shape. Her T2 Sarah Connor arrives totally shredded, and looks and behaves like an army operative. She has befriended pockets of survivalist sects all around Southern California and Mexico, and had been training John in the ways of militaristic strategy during his formative years until she was institutionalized in a psychiatric ward. John (Edward Furlong), now a punky preteen, is in a foster home when he finds himself attacked by a new Terminator, the T-1000 (Robert Patrick), before being rescued by another T-800 model (Schwarzenegger again), who informs him that future-John now reprogrammed the T-800 and sent it back in time to protect him from the T-1000. This time, Sarah is ready when John and the T-800 bust her out, and soon the trio are on the run together - a makeshift family of misfits on a mission to save the world from a terrifying apocalyptic fate.
What makes Sarah Connor perhaps the metric against which many modern American action heroines are judged is the gravitas and depth of Hamilton's performance and physicality, coupled with Cameron's sparkling scripts. We appreciate and understand Sarah's process as she grows and changes across the first two movies, plus the sixth franchise entry, Terminator: Dark Fate, Hamilton's return to the franchise. She remained in impossibly impressive shape, and looked capable of taking down just about anybody, human or cyborg, even into her 60s.