Christensen was born in Vancouver, British Columbia, Canada, the son of Alie, a speechwriter for the heads of large companies, and David Christensen, a software program writer and communications executive. His father is of Danish descent and his mother has Italian and Swedish ancestry. Christensen has an elder brother and sister, Tove and Hesja, and a younger sister, Kaylen. Raised outside Toronto Read more...

Christensen's first acting role was on the television series Family Passions, which aired on Canadian television in September 1993, at the age of twelve. The following year he acquired a minor role in John Carpenter's In the Mouth of Madness. From 1995 through 1999, he appeared in several movies and television shows, including Harrison Bergeron, Forever Knight, Goosebumps, The Virgin Suicides, and Read more...

While Christensen's critically acclaimed portrayal of a misunderstood teenager in Life as a House (2001) earned him Golden Globe and SAG Award nominations as well as the National Board of Review's award for Breakthrough Performance of the Year, the performance didn't receive widespread public notice. For his part in the movie, Christensen lost 25 pounds through a special diet. He eventually gained Read more...