While shooting this film, James Cameron often resorted to what he called "guerilla filmmaking" as a way of getting around acquiring permits needed to film certain scenes. This involved the production crew and actors quickly arriving at a specified location, shooting the scene and leaving before the police arrived. As a result, some of the people seen in a few shots are actual everyday citizens completely unaware they're in a movie. This was also used for re shoots with Cameron even calling and waking Arnold Schwarzenegger once at 3 am to meet him at a location already in full costume to quickly re-shoot a scene. Cameron also used this tactic to film the very last scene where Sarah drives off into the desert. Waiting for the heat to rise to the point that ripples could be filmed a highway patrolman appeared. Producer Gale Anne Hurd convinced him they were working on a UCLA film project and he allowed them to finish.
Arnold Schwarzenegger worked with guns every day for a month to prepare for the role. The first two weeks of filming he practiced weapons stripping and reassembly blindfolded until the motions were automatic, like a machine. He spent hours at the shooting range and practicing with different weapons without blinking or looking at them when reloading or cocking. He also had to be ambidextrous. He practiced different moves up to 50 times. He wound up garnering a compliment in "Soldier of Fortune" magazine for his realistic handling of the guns on camera (whereas the magazine usually lampoons movies for their inaccurate depictions of weapons use).
Arnold Schwarzenegger tried to avoid Linda Hamilton and Michael Biehn as much as possible since the Terminator was trying to kill them, not form connections.
James Cameron got the idea of giving Arnold Schwarzenegger even fewer lines in the film than Schwarzenegger's earlier film Conan le Barbare (1982), in which Schwarzenegger only had 24 lines. In this film, Schwarzenegger has only 14 lines and 21 minutes of screen time.
Arnold Schwarzenegger was originally being considered to play Kyle Reese because the producers were thinking of O.J. Simpson to play the Terminator. The bodybuilder-turned-actor had made something of a name for himself in Le Privé (1973), Arnold le magnifique (1977) and Conan le Barbare (1982), and when Orion Pictures executive Mike Medavoy met the actor at a party, he sent him the script for consideration. However, James Cameron had envisioned Reese as a non-bulky and more sensitive man, so he was less than enthusiastic about casting a former Mr. Universe in the pivotal role. Largely on Medavoy's insistence, Cameron went out to meet and have lunch with him anyway; he later admitted that he had planned to pick a fight with Schwarzenegger so that he could claim that the actor was impossible to work with. But against his expectations, they got along just fine, and Schwarzenegger showed great enthusiasm for the script, especially its dark antagonist character. Schwarzenegger talked at length about how this Terminator should behave, like always scanning the surroundings and handle weapons without looking at them. It was then that Cameron had a change of heart, and offered Schwarzenegger the title role of the Terminator. Schwarzenegger initially declined, saying that he didn't want to play the bad guy, and because the character had fewer than 20 lines, but Cameron told him that "this movie is not about the hero. It's about The Terminator," and promised him that he wouldn't need lines to have a presence. Schwarzenegger then gladly accepted, even overruling his agent who advised him against playing villains. Cameron and Schwarzenegger have been good friends ever since.
William Wisher: (at around 38 mins) The co-writer of this film plays the police officer who attempts to assist the Terminator after he is thrown from the hood of the car, but gets knocked unconscious for his trouble. Wisher has a cameo in the sequel Terminator 2 : Le Jugement dernier (1991) as well, where his character seems to have a look of recognition upon seeing the new Terminator.
James Cameron: Cameron's voice is heard three times in the movie: as Sarah Connor's date on the answering machine and twice as a manager of Tiki Motel, who is heard (but not seen) speaking to Sarah and then again answers the phone when the Terminator calls.
James Cameron: [strong women] Many of Cameron's films (Piranha 2 : Les Tueurs volants (1982), Aliens, le retour (1986), Abyss (1989), Terminator 2 : Le Jugement dernier (1991), Titanic (1997)) champion strong women, both mentally and physically.
James Cameron: [Biehn's hand] (at around 42 mins) Michael Biehn's character gets bitten on the hand by another character. See Aliens, le retour (1986) and Abyss (1989).
James Cameron: [feet] The Terminator often steps on objects, crushing them. In the future, there is a close-up of tank treads rolling over human skulls.
James Cameron: [nice cut] (at around 1h 13 mins) Sarah Connor's burning photo fades into Sarah sleeping into Kyle Reese's arms.