reene was born in Jacksonville, Florida to Joe and Michele Greene. She grew up in Middleburg and Jacksonville, and went to University Christian School before transferring to Wolfson High School when she was in tenth grade. She moved to Los Angeles, California at the age of 17 to pursue an acting career. Greene has one sibling, an older brother named Joe, who still resides in Jacksonville with her parents.
Greene is good friends with her Twilight co-stars Kellan Lutz and Jackson Rathbone, who she knew before filming the movie.
Greene initially planned to become a model, but was told that she wasn't tall enough to be a runway model and should instead focus on commercials. After taking commercial and acting classes, she fell in love with acting and realized that she preferred it over modeling. Greene thus graduated high school early at the age of 17 and moved to L.A. to pursue an acting career. Though her career is still evolving, Greene has appeared as a guest on many popular television programs, such as Punk'd and Crossing Jordan, as well as in an iPod commercial. Greene's big break came in 2008 when she was cast as Alice Cullen in Twilight, a film based on the novel of the same name by Stephenie Meyer. Greene will be reuniting with her Twilight co-star Kellan Lutz in the upcoming movie Warrior.