On July 15, 2007, he returned to series television as one of the lead males in Lifetime Television's comedy–drama Side Order of Life. Priestley made a guest appearance on NBC's My Name Is Earl in 2008. He played Blake, Earl's better-looking and more successful cousin. That year, Priestley directed five episodes of Secret Life. Priestley directed the episode when Tori Spelling returned to 90210. In 2009 Priestley directed and co-produced all 12 episodes of the Web series The Lake on TheWB.com. In December 2009 along with Dougray Scott, Brian Cox, and Eddie Izzard, Priestley was featured in The Day of the Triffids, written by Patrick Harbinson, whose credits include ER and Law & Order. The drama is based on John Wyndham's best-selling post-apocalyptic novel, The Day of the Triffids.
On July 9, 2007, he revealed on Late Night with Conan O'Brien that he had become an American citizen several weeks earlier.