Dewan was born in Hartford, Connecticut, the daughter of Nancy Lee (née Bursch) and Darryll Dewan, who was starting running back for the 1972 Notre Dame Football Team. Dewan is of half Lebanese ancestry. Her parents divorced when Dewan was young and her mother remarried to Claude Brooks Smith. During high school at Grapevine High School, in Grapevine, Texas Jenna was a varsity cheerleader and won many dance competition awards. She graduated in 1999 and was voted prom queen her senior year. She went to USC and was a member of Pi Beta Phi. As of 2005, she has been dating her co-star in Step Up, Channing Tatum.