Many Saw characters who were minor in their debut installment get larger roles in later entries of the franchise.
- Allison Kerry appeared briefly at crime scenes in Saw and then became a major character in Saw II.
- Amanda Young was present in one flashback in Saw, then became a main character in Saw II and III.
- Eric Matthews appeared briefly in Full Disclosure Report. He then became the protagonist of Saw II.
- Mark Hoffman first appeared briefly as a crime scene technician at the scene of Troy's trap in Saw III, being even credited as "Forensic Hoffman". Likely because every other Jigsaw killer and major cop at the time (besides Rigg and Eric) was killed off in the previous installments, Hoffman is suddenly a seasoned detective and Jigsaw apprentice from Saw IV onwards, and becomes the new Big Bad up to Saw 3D.
- Jill Tuck first appeared briefly in non-canonical content within the comic book Saw: Rebirth, and was then seen briefly in a flashback with no lines in Saw III. Starting by Saw IV, she becomes a supporting and later main character.
- Peter Strahm was introduced as a supporting character in Saw IV, then became the lead protagonist of Saw V.
- In Saw, Adam mentions that he has a best friend named Scott Tibbs, who stabbed him with a rusty nail on his fourth birthday. Scott then became the central character of The Scott Tibbs Documentary, where he's shown to be the frontman of a band named Wrath of the Gods, the logo of which appears on one of Daniel Matthews' T-shirts in Saw II (whose DVD releases where the short film was included) and a flyer Adam gives to Amanda in a deleted scene of Saw III.
- Oswald McGillicutty's name is on a newspaper clipping in Tapp's apartment in Saw. He later appeared in the first video game.
- Jeff Ridenhour is put in a trap in Saw and has muffled lines because his mouth is gagged. He speaks and appears in another trap in the first video game.
- That wasn't the first plan to bring him back in a larger role, however. According to the original script of Saw IV, he was meant to return in said film as a Jigsaw accomplice, being the one who placed the explosive Billy that knocked out Perez in the final film.
- Carla Song doesn't have much screentime in Saw. She's put in a trap in the second video game.
- Pamela Jenkins debuted as a reporter who only appears at the police conference announcing the end of the Jigsaw killings in Saw V. She gets a larger role in Saw VI, and her attempt to write a book about the Jigsaw case is alluded to via various notes in the first video game.
- Gordon's lawyer Brett is a What Could Have Been example. In Saw IV, he was going to be the victim who had to set up the various traps seen in the film before Art Blank took his place.
