Backus moved with friend Rob McElhenney from New York City to Los Angeles during pilot season of 2003. Shortly after arriving, Backus landed his first role in "Benjamin Splits", while McElhenney developed the sitcom "It's Always Sunny in Philadelphia". After landing supporting roles in NBC's hit show "Will & Grace" and Fox's "The O.C.", Backus starred opposite Dominique Swain in Nick Vallelonga's "All In". He returned to television in Malik Bader's "HUGE" in which he portrayed a struggling frontman of an indie rock band. He starred in "3 Days Gone" along with Patrick J. Adams, "Nothing Personal" with Paz de la Huerta, and "Elevator" with John Getz and Anita Briem.