An experienced stage performer, Thorne has worked frequently with the NYC acting troupe Naked Angels and at the now-defunct Malaparte., a theater company where actor Ethan Hawke directed her in Jonathan Marc Sherman's play "Veins and Thumbtacks". In 1997, the dark-haired actress joined the ensemble of NBC's "Homicide: Life on the Street" as Detective Laura Ballard, a seasoned homicide detective recently transplanted to Baltimore from Seattle. She made her film debut, billed as Calliope Thorne, in "Ed's Next Move" (1996) and also appeared in "Turbulence" (1997), alongside Ray Liotta and Lauren Holly. She also had small roles in “Next Stop Wonderland” (1998) and “Sidewalks of New York” (2001) as well as a bit part as an FBI agent in “Analyze That,” (2002).

Before "Homicide" and "Rescue Me," Thorne was no stranger to critically acclaimed television drama. She also portrayed the ex-wife of Baltimore Detective James McNulty (played by Dominic West) in HBO’s “The Wire.” Other television appearances include USA’s “The Street” as well as NBC’s “Third Watch” (NBC) and two “Law & Order” spin-offs: “L&O: Special Victims Unit,” and “L&O: Criminal Intent.” She also appeared in the critically appraised Comedy Central series “Strangers with Candy,” and had a small role in the HBO original movie “Hysterical Blindness” (2002)

On the stage, she acted opposite Eric Bogosian and Sam Rockwell in “The Last Days of Judas Iscariot,” directed by Philip Seymour Hoffman, as well as “Gone Home,” “Joe Fearless” and “The Country Club.”