Vaugier was born in Vancouver, the daughter of French immigrants. She grew up in a Roman Catholic, French-speaking household. She attended Crofton House School, a girls private school, for 10 years until she transferred to Magee Secondary School, which offers a flexible academic program for professional and pre-professional student athletes, artists and musicians (SPARTS), for the last two years of high school. She has an older brother, Jason.
Vaugier played the role of young, upstart Maria Alcobar in a 1995 episode of Highlander: The Series. In 2004, she played Lindsey Kellogg on the short-lived Fox Television series North Shore. She has also had guest-star spots on Veronica Mars, Supernatural, The Outer Limits, Higher Ground, Andromeda, Smallville, and Charmed. She also appeared in the Emmy Award nominated miniseries The Beach Boys: An American Family where she portrayed Mike Love’s wife, Suzanne. Vaugier also completed a starring role in MOW Veiled Truth for the Lifetime Network. She is also known for her role during the first two seasons of One Tree Hill, as Nicki, Jake's (Bryan Greenberg) ex-girlfriend and mother to their child, Jenny.
From 2005–2015, Vaugier guest starred in twelve episodes of CBS's hit sitcom Two and a Half Men as Mia, a ballet teacher with whom Charlie Harper fell in love and almost married. In 2005, she also played the title character in the Painkiller Jane television movie for the Sci Fi Channel. She first became noticed by the science fiction community when she portrayed Dr. Helen Bryce, the love interest of Lex Luthor, on the WB's hit drama Smallville in 2002–2003.
Vaugier had a recurring role from 2006–2009 on the CBS show CSI: NY as Detective Jessica Angell. She left the show after the fifth season due to budget cuts.