Seventeen-year-old Julie is the protagonist of I Know What You Did Last Summer. Although the book has several points of view, Julie’s point of view, described with a limited third-person narrator, occurs in more chapters than any other character. Her habit of wearing pink clothes with her red hair is noted in Chapter 1. Her boyfriend Ray has called her a “rosebud with freckles” (5). She is close with her mother, Mrs. James, and lost her father when she was a little girl. After the accident, Julie wanted to contact the police, but she reluctantly entered into a pact with her three teen friends to keep the hit-and-run a secret.

Her guilt over killing the little boy, Daniel, in the accident causes her to send flowers to his funeral. She tells Ray, “I sent him flowers” (26), an arrangement of yellow roses. The antagonist tracks down the teens to take his revenge through Julie’s gift of yellow roses. Guilt changed Julie’s personality dramatically. Her mother notes how “her daughter seemed different—quieter, more studious. Her social life had fallen away to almost nothing, but that might simply have been because Ray was gone” (167).