Peter Killian Gallagher is an American actor whose career spans theater, film, and television. He began his career on the Broadway stage, where he earned a Tony Award nomination for his performance in the revival of "Long Day's Journey into Night." In film, he gained international recognition with Steven Soderbergh's independent film "Sex, Lies, and Videotape" (1989). His filmography includes successful titles such as "The Player," "While You Were Sleeping," and "American Beauty," for which he shared a Screen Actors Guild Award with the rest of the cast. However, he achieved mainstream fame through television with his iconic role as lawyer Sandy Cohen in the series "The O.C." (2003-2007). He has since maintained a consistent presence on the small screen, appearing in numerous series including "Law & Order: Special Victims Unit," "Covert Affairs," and "Grace and Frankie," demonstrating great versatility.