Greene was born in Jacksonville, Florida, the daughter of Michele, who works in insurance, and Joe Greene, a U.S. Marine who now owns his own concrete business. 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, particularly Kellan Lutz, whom she knew before filming the movie.
