Bush was born in Pasadena, California, the only child of Maureen Searson and Charles William Bush. Her mother runs a photography studio, and her father is an advertising and beauty photographer. She graduated from Westridge School for Girls in 2000, where she was a member of the volleyball team. At Westridge, she was required to participate in the theatre arts program. Bush stated: "Part of my school's requirement was to do a play. I was really irritated because I wanted to play volleyball and I had to go and do this play. But there was a moment after the performance when I realized I had gone and been somebody else. I thought, 'If I could do this for the rest of my life, I am set. ' It was like love at first sight. " At age 17, Bush was named the Tournament of Roses Parade Queen. She attended the University of Southern California (USC) as a journalism major until her junior year, where she was a member and Social Chair of the Kappa Kappa Gamma sorority.