After regretting her actions towards the shy, outcast Carrie White, Sue attempts to redeem herself by asking her boyfriend Tommy Ross to take Carrie to the Prom instead of her, unaware that her intentions are about to trigger horrifying events.
Sue lived with her father, mother, and sister and was a popular student at Bates High School. She was friends with Chris Hargensen and dated the popular athlete, Tommy Ross. Once after P.E. class, Sue and her schoolmates witnessed as Carrie, an outcast student, and daughter of a delusional, religious mother, had her first period in the shower, ignorant of what was actually happening to her. Sue, Chris, Norma, and the other girls coldly mocked the horrified Carrie, throwing tampons on her. Sue was stopped as their teacher Miss Collins arrived and told her about what was happening. When Sue later arrived home, Carrie's mother was there preaching over her mother. Sue and the other girls were later confronted by Miss Collins who told them they would be punished for what they did to Carrie. The girls were then forced into extreme physical exercise until Chris defied the teacher and called her schoolmates to join her. Feeling guilty and regretful for her actions towards Carrie, Sue only told Chris to "Shut Up". Sue later had the idea of making things better for Carrie by persuading Tommy into taking her to the prom instead. Tommy agreed, and the two were interrogated by Miss Collins on their true intentions. Sue, however, was unaware of Chris' plans for that same night, after Chris was expelled from the Prom. Sue left home to see sneak and see how things were going at the Prom, and found out that Carrie and Tommy were elected Queen and King of the Prom, and rejoiced. Sue then noticed the ropes armed around the stage, and spotted Chris and Billy hidden below Carrie and Tommy, ready to humiliate her in front of everyone. Miss Collins assumed Sue went there to ruin Carrie's perfect moment and ignoring the girl's warnings about Chris and Billy, Miss Collins expelled Sue out of the Gym. Outside, Sue desperately screamed to be allowed inside, until Freddy and Kenny appeared trying to squirm their ways out and were suffocated as Carrie, enraged, forced the two, suffocating them between doors. Sue tried to get in and witnessed the massacre happening there. Afraid of Carrie and of the events, she went away from there. Traumatized over the deaths of Tommy, her friends, schoolmates, and teachers, Sue became haunted by nightmares of Carrie.
The Rage: Carrie 2 (1999)20 years later, as The Night Of The Prom and Carrie's "supposed" vengeful role in it became an "Urban Legend", Sue admitted herself in the Arkham Institue due to her intense trauma, and at some point discovered about the existence of telekinesis, the power of one to move objects with his mind, which for years she did not believe there was. After discharge, and still haunted by memories of the past, Sue became a school counselor at the reformed Bates High School. After a girl known as Lisa Parker committed suicide on campus, Sue confronted her only friend Rachel Lang, a withdrawn outcast, who told her and Sheriff Kelton that Lisa went out with Eric Stark that weekend. After the constant visits of girls crying after being dumped by boys, Sue insisted to Sheriff Kelton that it should be investigated since Eric having sex with Lisa was Statutory Rape. Kelton, however, asked if Sue was not actually still trying to save a girl who died years before, and Sue remembered the incident in the shower. Sue confronted Rachel and offered her help and confidence. Rachel initially agreed, and Sue told her that twenty-three years before, she tried to help someone, and it "backfired horribly". Rachel's schizophrenic mother Barbara happened to be at the Arkham asylum Sue had been and asked Rachel about her fear of becoming what her mother was, which was "perfectly normal" on her age. As Sue talked, however, Rachel felt disturbed and caused Sue's mug to fall from her table, causing Sue to suspect Rachel was a carrier of telekinesis. Sue then called Rachel in, and attempted to make her speak out about her inner gift. Rachel then tried to leave, reluctant, and Sue forced her to stay, insisting that they should talk. Stressed out, Rachel caused Sue's dome to explode on her table, and left. Sue, horrified to what Rachel was able to do, remembered the massacre she witnessed. Sue later visited Barbara at Arkham and asked if Barbara had ever seen objects moving by themselves as Rachel grew up. Barbara told her about how terrifying children can be, and revealed that Rachel's real father was Ralph White, Carrie's father, a secret she kept after the events of the prom night. Sue then approached Rachel and took her to the remains of the old campus, and told her what happened there. Sue then told Rachel about her real father, her half-sister Carrie White, and the gift they share, much for Rachel's revolt. Sue also told her about a Princeton lab that studied psychic abilities, where she could find help. Rachel, however, did not believe in anything and left. Sue's last attempt to help Rachel was to sneak in Arkham and take Barbara out, so they could find Rachel and tell her the truth. Sue was then told discovered Rachel left school with the popular student Monica Jones, which Sue estranged. Sue rushed to Mark Bing's house where a Party was happening, and heard screams from outside. She rushed to the locked front door calling out for Rachel, and as she tried to look inside, Rachel (unknowingly) kills Sue via impaling her in the head along with Brad with a fire poker.
- The infamous ending of Sue's nightmare scene where Carrie pulls her from underground was filmed backwards to be given a more dream-like tone.
- The scene has inspired scenes in several subsequent horror films and classics such as Alice's nightmare in Friday the 13th.
- Stills of Carrie feature Sue outside the gym, horrified as Freddy and Kenny got suffocated between the doors.
- Sue can barely be seen in the background trying to get in between the two as Carrie washes Norma away from them.
- In the original ending of the film, Sue was supposed to follow Carrie up to her house, where she finds Margaret White's dead body, confronted by her and witness the house's destruction. This would be the only direct dialogue between the two characters in the 1976 film. The idea was later used in the the 2013 remake.
- Sue does not become pregnant with Tommy's child, which excludes the whole abortion plot completely.
- She appears to have a sister, where as in the novel she appears to be the only child.
- The night of the prom leaves Sue traumatized, whereas in the novel she becomes different over her losses at the "The Black Prom".
- Sue sneaks into the prom, differently from the novel where she stays at home until she hears the sirens outside, as Carrie destroys the town. Sue discovers what actually happened after her mind is bonded to Carrie's through her telepathy.
- In the original script of the sequel, Sue manages to get inside the party and is burned to death by Rachel.
- While filming Carrie, actress Amy Irving was, along with her female castmates, asked out by director Steven Spielberg, with whom she eventually married and had children.
- Amy Irving portrayed Gillian Beavers, a girl with psychic powers in the The Fury, which was also directed by Brian de Palma.
- Amy Irving asked Brian de Palma for his blessing before she went back to the role of Sue Snell for the sequel.
- Amy Irving's real mother Priscilla Pointer portrayed Mrs. Snell in the film. A picture of the two can be seen in Sue's office in the sequel.
- When filming the ending scene in which Mrs. Snell attempts to calm down her horrified daughter, Amy Irving's intense acting caused Priscilla Pointer to call her "Amy".
- Amy Irving and Sissy Spacek also starred in the 2002 film Tuck Everlasting.