Wagner was born in Winston-Salem, North Carolina. She attended Ledford Senior High School in Wallburg, North Carolina and North Carolina State University. She graduated in 2001 with a bachelor's degree in business management.
As a teenager, Wagner also graduated from the Barbizon Modeling and Acting School in Raleigh and went on to be named Miss Barbizon.
In her younger days she was a favorite in Men’s Magazines Stuff and FHM ranking #90 on Maxim’s list of Hot Women of 2004.
Her first job in television was also on MTV as part of the cast of the hidden camera show Punk’d.
She is best known for being television host for talk shows and game shows. In 2008, she became one of the hosts of the competition game show Wipeout on ABC.
She also appeared television shows like Stargate: Atlantis, Monk, Dr. Vegas and Bones.
In 2006, she was regular on the short-lived Blade: The Series.
In 2013, Wagner returned to MTV for an episode of Teen Wolf Revelations where she interviewed some of the Teen Wolf cast at the midway point of Season 3. From Season 3B to Season 4, she was the host of Wolf Watch, the official Teen Wolf after show until Tyler Posey took over in Season 5.
Wagner returned to Teen Wolf in the season 3B finale. Her character apparently survived her "death" and has transformed into a shapeshifter known as a Werejaguar.