Dean Winters is most famous for playing the scheming Ryan O'Reilly on HBO's original series, Oz. Other roles have included Johnny Gavin on the FX series, Rescue Me; Raymond Caine on CSI: Miami; and Brian Cassidy during the first season of Law & Order: Special Victims Unit. Winters can be currently on Terminator: the Sarah Connor Chronicles as Charlie Dixon, as well as a recurring role on 30 Rock as Liz Lemon's former boyfriend, Dennis Duffy.