[6] Christensen made his acting debut in September 1993, when, at the age of 12, he played a supporting role on the German-Canadian television series Macht Der Leidenschaft/Family Passions.

[7] From 1995 through 1999, he appeared in several films and television series, including Harrison Bergeron, Forever Knight, Goosebumps, The Virgin Suicides, and Are You Afraid of the Dark?

[7] He acquired wider notice while starring in Fox Family Channel's television series Higher Ground in 2000, portraying a teen who was sexually molested by his stepmother, and then turned to drugs in his despair.

[13][14] Peter Travers of Rolling Stone wrote, "Hayden Christensen is sensational as Glass, finding the wonder boy and the weasel in a disturbed kid flying high on a fame he hasn't earned.

This was essential to solidify the story that Lucas was trying to tell: Anakin Skywalker's fall from grace and transformation into Darth Vader.

[18] Lucas agreed, and a suit was engineered to fit Christensen's frame, even including extensions to allow for the actor to attain Vader's 6 ft 6 in (1.98 m) height.

[19] In one of the most controversial changes made to the Star Wars original trilogy,[20] Christensen was inserted into the 2004 DVD release of Return of the Jedi, where he replaced Sebastian Shaw as the force ghost of the redeemed Anakin Skywalker.

[36] Christensen appeared opposite Mischa Barton in Virgin Territory, which was released directly-to-DVD in North America on August 26, 2008.

[37] The film, based on The Decameron, is about a group of people who escape the Black Plague epidemic by hiding out in a Tuscan villa in Italy.

[38] In October 2009, Christensen started shooting the horror film Vanishing on 7th Street, directed by Brad Anderson, with Thandiwe Newton and John Leguizamo.

[39][40] Christensen appeared in the crime drama Takers with Idris Elba and Paul Walker, released in the United States on August 27, 2010.

The first project, American Heist, starring Christensen, Adrien Brody and Jordana Brewster, started filming in June 2013.

[47] In 2015, Christensen starred in the film 90 Minutes in Heaven co-starring Kate Bosworth and directed by Michael Polish based on the best-selling novel by the same name.

In 2015, filming began of an unreleased World War II Nazi zombies horror movie titled Untöt, set to star Christensen.

[51] Christensen also received a voice credit as Anakin Skywalker jointly alongside Matt Lanter for the penultimate episode of the final season of the animated television series Star Wars: The Clone Wars entitled "Shattered" despite the fact the dialogue used for the episode spoken by Christensen was reused archival audio from Revenge of the Sith.

[69] In November 2013, Christensen collaborated with Canadian fashion chain RW&Co to release a men's clothing line inspired by his farm.

[75] He was featured in RED's Lazarus Effect Campaign, which is intended to increase awareness for its efforts to fight AIDS in Africa.