Sieber also originated the role in the show's London production. His many other Broadway credits include Chicago, Thoroughly Modern Millie, Beauty and the Beast, Into the Woods, and Triumph of Love. Sieber also starred in the ABC sitcom Two of a Kind with John Benjamin Hickey and Harriet Harris.

Spamalot currently stars Jonathan Hadary, Marin Mazzie, Michael McGrath, Martin Moran, Tom Deckman, Rick Holmes, and Jeffrey Kuhn. The show, which is based on the screenplay for Monty Python and the Holy Grail, won the 2005 Tony Award for Best Musical as well as Best Director for Mike Nichols.