She grew up in Simi Valley, California with her twin sister Jessica and younger sister Rebecca.
She first began performing in school productions in junior high and became heavily involved in Southern California's robust community theater scene during her teen years. Along with performing on the stage, Jenna also was featured in many commercials and television spots, as well as a few made-for-TV movies.
Green's big break came quickly when she landed the featured role of mean girl Libby Chessler on TV's "Sabrina the Teenage Witch". A decade after she first appearred, she's still most often recognized as Libby.
Green did guest spots on shows like ER and Dharma & Greg before moving cross-country in 2004 to make her off-Broadway debut in Bare as troubled teen sexpot Ivy.
After the still-tight Bare crew parted ways, the brunette beauty was cast as Nessa in the touring company of Wicked, her second major acting credit involving witches.
Jenna has a twin sister, Jessica.
She is 5 feet, 4 inches tall.