Jill Roberts is cousin of Sidney Prescott, daughter of Kate Roberts and was niece of Maureen Roberts. She is seemingly and innocent victim along with her cousin Sidney and everyone else but behind this persona is a fame-seeking, sociopathic, psycho who snaps after living her whole life in the shadows of her famous relative.
She is best friends with Kirby Reed and Olivia Morris. Trevor Sheldon is her ex-boyfriend who keeps tying to win her back. She is also friend of Charlie Walker and Robbie Mercer.
Jill first appears in Scream 4 as an innocent teenager who is dealing with betrayal of her ex boyfriend, Trevor. When Sidney comes back to Woodsboro, Jill states that she is not close to her cousin and when her friend Olivia is killed, she initially blames Sidney for causing the murder spree but later reunites with her cousin. Jill and Sidney share a family moment when Sidney states that she knows how Jill feels. Sidney on other hand is very protective of Jill and tries to protect her cousin from the killer at all costs.
In the finale, Jill is revealed to be the killer along with Charlie. Her plan was to become the 'new Sidney' and the sole survivor of the latest murders occuring in Woodboro. She states that all her life all she heard was about her cousin and the fame Sidney achieved from the original murder spree and now she wants to become another "survivor hero" herself. She planned to achieve this by teaming up with her friend Charlie in order recreate the original murders performed by Billy Loomis and Stu Macher. After succeeding doing this- she killed Charlie, stabbed Sidney and framed her(dead) ex-boyfriend Trevor. However, at the hospital, She discovered Sidney was still alive. In a desperate attempt to get away with the murders- she leaves her bed and attempts to kill her cousin once and for all. Sidney initially resists Jill's attempt but when Jill tries to kill Dewey, Gale and Judy, Sidney kills her cousin. The final scene shows reporters outside the hospital stating Jill to be a true Hero and a Survivor unaware of Jill's current fate. Jill finally managed to attain the fame she so desperately sought.