Barrowman, who did the quickstep with dance partner Kristina Rihanoff, told the BBC that it felt "absolutely wonderful" to win. The singing actor also said it was "a dream come true."
His competitors included "EastEnders" star June Brown, presenter Fern Britton, Business Secretary Vince Cable and comedian Ronni Ancona.
Among the judges were Bruno Tonioli and Len Goodman.
John Barrowman is best known for creating the role of Captain Jack Harkness in the first series of Russell T. Davies' revamped "Doctor Who" for BBC TV, from which his own spin-off series, "Torchwood," was created. He has also appeared in series 3 and 4 of "Doctor Who." The singing actor has also been seen as a judge on BBC1's reality TV casting shows "How Do You Solve a Problem Like Maria?," "Any Dream Will Do" and "I'd Do Anything" and was a celebrity skater on the ITV show "Dancing on Ice."
Prior to La Cage aux Folles, he was last seen on the West End musical theatre stage doing a stint in Chicago as Billy Flynn in 2004, and prior to that was seen at the National as Billy Crocker in Anything Goes (a role he had previously taken over in the previous West End revival at the Prince Edward Theatre, opposite Elaine Paige, in 1989). He also appeared as Dumaine in Shakespeare's Love's Labour's Lost during his National Theatre season, and subsequently made his West End straight play acting debut in A Few Good Men at the Theatre Royal, Haymarket in 2005. Among his other numerous West End credits are Matador, Miss Saigon, Beauty and the Beast, The Fix (Olivier-nominated for Best Actor in a Musical), Hair and Sunset Boulevard. On Broadway, he has appeared in Sunset Boulevard and Putting it Together. Barrowman will also star in a fourth season of "Torchwood."
For more information visit JohnBarrowman.com.