Bierko got his break in 1990 when he was cast opposite Valerie Bertinelli and Matthew Perry in the CBS sitcom Sydney; however, the production lasted just 13 episodes. He went on to make steady appearances in various television shows including Amen, The Powers That Be, Wings and Ally McBeal. Bierko may be best known for his role as Timothy in the 1996 action film The Long Kiss Goodnight, as Max Baer in the film Cinderella Man, as Tom Ryan in Scary Movie 4 and on the Broadway stage as Harold Hill in The Music Man, or as the lead in The Thirteenth Floor. He was also the original choice for the character of Chandler Bing on the sitcom Friends but turned it down. He had a small role as a jazz musician love interest for Carrie Bradshaw in the fourth season of Sex and the City. He had another small role as attorney Jeffrey Coho during the third season of the ABC television series Boston Legal and as a lead in the short-lived Unhitched. He was also cast as Dave Lister in the pilot for the American TV version of Red Dwarf, which was not picked up as a series. He appeared in 2001's Kate & Leopold in an uncredited role, and in TV's as Andy Eckerson, a United StatesDeputy Marshal who is working with the SVU to recapture an escaped convict. Bierko also appeared in the Lifetime dramedy series UnREAL as Chet, the "eccentric and drug-using" creator of a reality dating show.
Theater roles
Bierko was slated to appear on Broadway in the Manhattan Theatre Club production of To Be or Not to Be but withdrew from the production August 29, 2008, for unspecified reasons. He starred as Sky Masterson in the Broadway revival of Guys and Dolls which began performances at the Nederlander Theatre on February 5, 2009, and officially opened on March 1, 2009. The production closed on June 14, 2009 after 113 performances. He performed the role of Peter in the 2011 New York Philharmonic production of Stephen Sondheim's Company with Neil Patrick Harris, Patti Lupone and Stephen Colbert. Bierko was slated to replace Bertie Carvel as Miss Trunchbull in Matilda the Musical at the Shubert Theatre along with Jill Paice as Miss Honey on September 3, but did not start performances until September 17 due to a "minor injury". On November 19, it was announced that Bierko will not return to the role of Miss Trunchbull due to "medical circumstances", following a shoulder injury sustained during rehearsals.