Born in Charlottesville, VA, Campbell grew up in the Southern city, attending Western Albemarle High School as a teenager. The youngster also happened to be an heir to the Champion spark plug fortune, which sounded better than the reality, since the small inheritance he received at age 18 was gone almost immediately. Meanwhile, he graduated from high school in 1979, where he had played football and performed in a student production of "The Man Who Came to Dinner." Relocating to Chicago, IL to be near his father, Campbell attended the American Academy of Art with the intention of becoming a comic book artist. But his passion switched to acting after taking classes at the suggestion of a friend. Deciding to pursue the craft seriously, he studied at the Ted Liss Studio for the Performing Arts, as well as at the Players Workshop of Second City in Chicago. After appearing in local regional theater, Campbell left the Windy City and headed to Los Angeles to pursue acting as a professional, while continuing his training at Howard Fine.Campbell soon made his television debut with guest starring roles in episodes of "Family Ties" (NBC, 1982-89) and "Hotel" (ABC, 1983-88), before landing his first series regular role that same year, playing the gay lover of Steven Carrington (Jack Coleman) on the popular primetime soap "Dynasty" (ABC, 1981-89) during the 1984-85 season. While his character failed to survive the infamous "Moldavian massacre" cliffhanger, Campbell went on to distinguish himself as a stalwart player capable of projecting heroic qualities. For two seasons, he played rookie Chicago detective Joey Indelli on the stylish cop drama "Crime Story" (NBC, 1986-88) and soon made the leap to the big screen in the role of a mysterious man who seemingly survived from prehistoric times in "Call from Space" (1989). Campbell next landed a starring role as reluctant superhero Cliff Secord in Disney's "The Rocketeer" (1991). Cast opposite a young Jennifer Connelly, Campbell began to date the actress offscreen for five years until the pair ended their relationship in 1995. Campbell went on to work with Francis Ford Coppola in the film adaptation of Bram Stoker's "Dracula" (1992) and appeared as Lieutenant Pitzer in the lavish Civil War epic "Gettysburg" (1993). Returning to stage work, Campbell appeared as Laertes in Stephen Lang's 1993 production of "Hamlet." That same year, he landed a starring role on the short-lived romantic detective series "Moon over Miami" (ABC, 1993) and received critical acclaim for his role as a gay gynecologist in Armistead Maupin's "Tales of the City" (PBS, 1993). Alternating between stage work and the small screen, Campbell went on to star in the Los Angeles production of "Fortinbras," for which he won a 1997 Ovation Award for Best Lead Actor, and reprised his "City" role in "More Tales of the City" (PBS, 1998) and "Further Tales of the City" (PBS, 2001). He next nabbed the lead role of Rick Sammler on the drama "Once & Again" (ABC, 1999-2002), for which he received considerable critical acclaim. Campbell's earnest and touching performance as a divorced father trying to find love earned him a People's Choice Award for Favorite Male Performer in a Television Series, as well as a Golden Globe nomination in 2000. Though the show struggled with ratings, it did manage to find a loyal audience, with Campbell appearing for three seasons, providing him with some much deserved exposure and dependable paycheck.A diverse actor, Campbell went on to appear as an abusive husband opposite Jennifer Lopez in the thriller "Enough" (2002) and landed a supporting role in another Civil War-era epic, "Gods & Generals" (2003). Returning to series television the following year, Campbell joined the cast of the sci-fi series "The 4400" (USA Network, 2004-07), a drama that centered on the stories of 4,400 people who mysteriously disappeared over a period of 50 years. The following year, Campbell added to his varied résumé by appearing in a multi-episode arc on the popular drama "The OC" (Fox, 2003-07), portraying magazine editor Carter Buckley. Because Campbell decided to spend 13 months circumnavigating the globe on a sailboat in 2005, his character on "The 4400," Jordan Collier, was killed off, though he did manage to return for the show's fourth and final season. Meanwhile, Campbell had a recurring stint on the short-lived "Shark" (CBS, 2006-08) before playing a detective desperately looking for his partner (Michael Rooker) before a meteor crashes into Earth in the aptly-named miniseries "Meteor" (NBC, 2009). Returning to series television, Campbell starred as a politician running for mayor in the acclaimed crime drama, "The Killing" (AMC 2011-13; Netflix, 2014), which explored the murder investigation of a young girl from the perspectives of various people connected to the event.