Carter was born in Toronto and raised in Winnipeg, Manitoba. She attended Balmoral Hall School where she was a dancer and took part in school plays including The Wizard of Oz, in which she played Dorothy. She was in the prestigious Royal Winnipeg Ballet. Carter was also on the debate team and named one of the top three public speakers in the world. She competed in various countries including Austria, England, and Argentina.
After graduating high school, Carter moved to Switzerland where she studied fine arts at Neuchâtel Junior College for one year. She subsequently attended Ryerson Theatre School in Toronto. At some point Carter took time off from acting, spending time in India and Cuba, where she worked in an orphanage.
Carter's early television career included appearances in Wolf Lake, Dark Angel, and Undeclared, and she was also cast in minor screen roles in Final Destination 2 and Mindstorm, where she appeared alongside Eric Roberts, Michael Ironside, and Antonio Sabato Jr.
Carter first appeared as a major character in a television role in 2003 when she played Allie Bennett in Black Sash and the following year she also appeared in three episodes of Smallville, she played fan favorite Alicia Baker, who has a romantic relationship with Clark Kent.
In 2006, Carter starred in the film DOA: Dead or Alive, playing the character Helena Douglas, a fighter who enters a martial arts contest. The following year she also starred in the film Killing Zelda Sparks as Zelda Sparks.
Carter's later television career has included playing the character Madeline Poe, a rookie prosecutor in Shark between 2006 and 2008, appearing in all 38 episodes of the series. In 2009 she also appeared in three episodes of CSI: NY, as the character Haylen Becall, a forensic school graduate.
Carter became a regular character, Maggie, on the TNT series Falling Skies, which debuted in June 2011. An apocalyptic alien invasion story, season 2 began on June 17, 2012 and concluded on August 19, 2012. Season 3 premiered June 9, 2013. On the heels of Falling Skies airing its series finale, Carter booked a recurring arc on CBS’ Hawaii Five-0 as a potential love interest to Steve McGarrett.
Carter released a solo album Before Three in December 2009.
She is part of the duo SanguinDrake, founded in 2010. As of December 2012, the band has released four self-produced music videos on their website. On May 12, 2012 SanguinDrake released their first album Pretty Tricks.
On June 19, 2011, Carter was one of thirty-five climbers who scaled Mount Shasta to raise money for the Breast Cancer Fund, for which she is a spokesperson. Her mother and aunt have both had breast cancer. She has also hiked the West Coast Trail.