She is a cruel bully who is best friends with the evil Chris Hargensen.
At the start of the movie in the girl’s locker room Carrie experiences her first period, but has no idea what it is, she starts panicking and thinks something worse is happening to her. Norma and Chris start mockingly throwing tampons at her, and enjoy her distress. Carrie is eventually saved from the torment by the gym teacher Miss Collins, who punishes the bullies with a boot camp style detention, with the threat of being banned from the prom if they do not attend.
Chris gets herself banned from prom after an argument with Miss Collins, and gets Norma to help her with an evil plan to humiliate Carrie at the prom. Norma replaces the prom king and queen votes with fake ones that are rigged so that Carrie ends up being crowned queen, with Tommy Ross as king. This is done so that when Carrie gets on stage to be crowned queen, Chris can pour a bucket of pig’s blood on top of her and humiliate her in front of everyone.
At the prom, Carrie and Tommy get called up on to the stage as winners, thanks to Chris and Norma’s villainous scheming. Chris pulls on the rope which causes the bucket to drench Carrie with blood. The majority of the room is stunned into silence by what happens, except for evil Norma, who absolutely loves Carrie’s humiliation and points and laughs at her. The bucket then falls and cracks Tommy on the head, knocking him out, which Norma finds hilarious too.
Carrie then starts hallucinating, thinking everyone in the room is laughing at her. She uses telekinesis to trap everyone remaining inside the school and manipulates things around her to electrocute and burn everyone to death. During this she causes a hose to spray Norma, which causes her to fall into a table and get knocked out, she is then burned to death with everyone else inside the school.
The character of Norma Watson has appeared in other Carrie movies as well, with each portrayal having similarities, but also slight differences. She was portrayed by Katharine Isabelle in 2002 and Zoë Belkin in 2013. But in both these roles the character was called Tina Blake.