Peter Gallagher Sandy Cohen Actor Ben McKenzie Ryan Atwood Actor Kelly Rowan Kirsten Cohen Actor Adam Brody Seth Cohen Actor Mischa Barton Actor Rachel Bilson Summer Roberts Actor Melinda Clarke Julie Cooper Actor Alan Dale Actor Olivia Wilde Guest Star Shannon Lucio Guest Star Johnny Messner Guest Star Billy Campbell Guest Star Amber Heard Guest Star Shaun Cozzens Guest Star Carrie Ann Nagy Guest Star John Michael Vaughn Guest Star Josh Schwartz Executive Producer Doug Liman Executive Producer McG Executive Producer David Bartis Executive Producer Robert DeLaurentiis Executive Producer