After graduating from high school, Durance moved to Vancouver, British Columbia, to pursue her interest in acting professionally. "I wanted to get my feet wet in a smaller area than Los Angeles when I gave it a try", Durance has said. She continued to study acting, starting out with background work, graduating to commercials, and then guest-starring roles, landing more substantial roles each time. In 2004, she guest-starred on The Chris Isaak Show playing Ashley, a woman on a date with Chris. In Tru Calling, her character was a contender in a beauty pageant opposite Eliza Dushku's character. On the Sci-Fi Channel, she played an intergalactic librarian in Andromeda and a love interest for Teal'c in Stargate SG-1. She also played a sister to one of the leads in the Canadian show The Collector.

Durance is perhaps best known for her role as Lois Lane on the television series Smallville. She was a frequent guest star for the fourth season of the show (2004-05) and joined the regular cast for the fifth season (2005-06), sixth season (2006-07), seventh season (2007-08), and eight season (2008-09), being, for the first time on the series, one of the main characters on many episodes. Durance appeared on The Howard Stern Show in September 2004 after she had already filmed a number of her first episodes on Smallville. She has also starred in several films credited as Erica Parker, including the 2003 horror film, House of the Dead, in which she appears topless.

She was listed as the highest new entrant and cover girl in FHM's May 2006 issue, including the World's 100 Sexiest Women at #38 and was listed by FHM at #20 in the World's 100 Sexiest Women in 2007 and she was also at #15 by FHM in the World's 100 Sexiest Women in 2008. She was also the October 2007 cover girl for Maxim. On October 9, 2006, she again appeared on The Howard Stern Show to promote the DVD release of The Butterfly Effect 2. In 2009, Erica will star as Heather in Ecstasy, based on the #1 bestselling book by Irvine Welsh. On August 26, 2008, Durance was nominated for Best Performance by an Actress in a Leading Role in a Dramatic Program or Mini-Series, according to the Canadian Press.

• Sleeping with the Lion (2009) (announced) .... Chandler Vick
• Final Verdict (2009) (TV) (filming) (rumored) .... Megan Washington
• Robin Hood: Beyond Sherwood (2009) (TV) (post-production) .... Maid Marian
  
• "Smallville" .... Lois Lane (95 episodes, 2004-2009)
  ... aka Smallville Beginnings (USA: rerun title)
  ... aka Smallville: Superman the Early Years (UK: promotional title)
       - Stiletto (2009) TV episode .... Lois Lane
       - Eternal (2009) TV episode (credit only) .... Lois Lane
       - Hex (2009) TV episode .... Lois Lane
       - Turbulence (2009) TV episode (credit only) .... Lois Lane
       - Infamous (2009) TV episode .... Lois Lane
        (90 more)
• I Me Wed (2007) (TV) .... Isabelle Darden
• The Butterfly Effect 2 (2006) (V) .... Julie Miller
• Stranded (2006) (TV) .... Carina
• "The Collector" .... Rachel Slate (1 episode, 2004)
       - Another Collector (2004) TV episode .... Rachel Slate
• "Stargate SG-1" .... Krista James (1 episode, 2004)
  ... aka Porte des étoiles, La (Canada: French title: dubbed version)
       - Affinity (2004) TV episode .... Krista James
• "Andromeda" .... Amira (1 episode, 2004)
  ... aka Gene Roddenberry's Andromeda (USA: complete title)
       - Time Out of Mind (2004) TV episode .... Amira
• "Tru Calling" .... Angela Todd (1 episode, 2004)
       - Drop Dead Gorgeous (2004) TV episode .... Angela Todd
• "The Chris Isaak Show" .... Ashley (1 episode, 2004)
       - Let the Games Begin (2004) TV episode (as Erica Parker) .... Ashley
• The Bridge (2004/I) .... Amy
• Devil Winds (2003) (TV) (as Erica Parker) .... Kara Jensen
• House of the Dead (2003) (as Erica Parker) .... Johanna
  ... aka House of the Dead (USA: recut version)
  ... aka House of the dead: Le jeu ne fait que commencer (Canada: French title)
• 111 Gramercy Park (2003) (TV) (as Erica Parker) .... Maddy O'Donnel
• The Untold (2002) (as Erica Parker) .... Tara Knowles
  ... aka Sasquatch (Canada: English title: DVD title) (USA: DVD title)
  ... aka Inexplicable (Canada: French title)