Rosalie Lillian Hale was born to a middle-class family in Rochester, New York in 1915. She was clearly the favorite of her parents, with two younger brothers.
Rosalie dreamed of a lavish life - a life with a rich husband and children as beautiful as she was. Her parents influenced her want of material things. She wanted a big house that someone else would clean, with a large lawn that she would play with her children on.
There was only one family that had what her parents wanted - the Kings. Royce King owned the bank Rosalie's father worked in. His son, Royce II, and Rosalie began dating. The engagement went quickly too and wedding plans were made. Rosalie couldn't help but feel something was missing from her relationship with him. She soon began wanting what her good friend, Vera, had - a husband who wasn't necessarily rich, but one that loved her and was there for her, and a small baby they could raise together lovingly.
One night she went to Vera's, and while walking home she realized how late it was and she wished that she had thought to call her father to escort her. On the way, she saw several drunken men. One turned out be Royce. He grabbed Rosalie and he and his friends beat and raped her and left her for dead in the street.
Carlisle Cullen found her through the scent of her blood. He saved Rosalie that night by turning her into a vampire. Rosalie was angry and devastated over not being able able to have the life and children she wanted. After becoming a vampire, she kills Royce and his friends while being careful not to spill a drop of blood. Since then, Rosalie prides herself on never having to drink human blood.
Two years later, she found Emmett being mauled by a bear and brought him back to Carlisle. She begged for him to save the dying Emmett, who reminded her of Vera's little boy, by changing him into a vampire. The two were soon married. Rosalie and Emmett currently reside in Forks, Washington, but they often live away from the family as a married couple. Currently she is the only one, aside Carlisle that has kept her last name on the grounds that she never wanted to be a vampire in the first place.
In Twilight, Rosalie is jealous of Bella because she's human and can choose any life she wants.
In New Moon, she mistakenly reports to Edward that Bella is dead after she supposedly commits suicide, though Bella was actually just partaking in the sport of cliff-diving. He then proceeds to travel to Italy, desiring to have the Volturi kill him, only to be stopped by Alice and Bella. After returning to Forks, Bella asks the Cullens to vote on whether she should become a vampire. Edward and Rosalie are the only ones against the idea.
In Eclipse, Rosalie reveals her past to Bella, hoping that she'll decide to stay human so she could have the life and children she couldn't have.
In Breaking Dawn, Rosalie and Alice help Bella prepare for her wedding to Edward. During their honeymoon,
Bella learns she's pregnant, and Carlisle tells them to return home immediately. Edward wants Bella to have an abortion, but she refuses, and contacts Rosalie for support, knowing that she has always wanted to have children. She stays by Bella's side until Renesmee is born, and takes care of her during Bella's painful transformation into a vampire.